It seems like his intent might be to deny the existence of a historical Buddha:
None of the claims that scholars and devotees have made about the Buddha appear to have been accepted unanimously. My own inclination, therefore, is to adopt an attitude similar to that expressed by David Drewes –
“Of course, it is possible that there was some single, actual person behind the nebulous ‘sramana Gautama’ of the early texts, but this is very far from necessarily the case… There may similarly have been an actual person behind the mythical Agamemnon, Homer, or King Arthur; Vyasa, Valmiki, Krsna, or Rama, but this does not make it possible to identify them as historical. If we wish to present early Buddhism in a manner that accords with the standards of scientific, empirical inquiry, it is necessary to acknowledge that the Buddha belongs to this group.”  Some thoughts on the “historical” Buddha & “authentic” Buddhism | Trusting in Buddha
The Buddha was, according to millions of Buddhists today and throughout history, more than a legendary figure like King Arthur or Odysseus.
It’s definitely written from a skeptical perspective. I would say that he understates how specific the old texts actually are about the Buddha- he says that the Buddha is treated generically, but there is actually quite a bit of very specific information about his family and affiliations, and if you read the longer suttas and vinaya accounts it’s clear that you’re dealing with the personality of a specific individual rather than a generic omniscient ‘sage’ persona.
That being said I think there’s a distinction to be made between saying that the Buddha existed as a historical personage, and saying that the details of the stories that come down to us can be treated as history. Over the centuries, many Englishmen claimed that a certain rock, cave, or hollow in their home town was somewhere that King Arthur had spent the night or left a footprint, but that isn’t the same thing as history.
It’s interesting to me that some of the earlier Western scholars seem to have been more open to the idea that the claims of there being previous Buddhas was more than just myth making. There are several things in and outside the sutras that suggest that there could be some factual basis that could be drawn out.
When the details of the Buddha’s life according to the Pali canon are generally treated as history, they come together rather well as a full biography. Nonetheless, there may be some literary embellishments in the original texts, which was common in the ancient world.
One difference between the Pali texts and the Arthuriana or the Ramayana is the relative lack of literary quality in the Pali collection. Very few of the suttas present compelling or well-composed narratives.
You aren’t alone in saying this, many many people very exposed to these texts say this, but I have always found the Pāli texts rather pretty and decent-to-read. I might be alone in thinking this, though.
This is one reason why I prefer Mahayana sutras over Pali suttas, and why I am Mahayana rather than Theravada, even though I have sincere respect for both traditions of Buddhism.
As far as the historicity of the Mahayana sutras:
John W. Pettit, while stating, “Mahayana has not got a strong historical claim for representing the explicit teachings of the historical Buddha”, also argues that the basic concepts of Mahayana do occur in the Pāli Canon and that this suggests that Mahayana is “not simply an accretion of fabricated doctrines” but “has a strong connection with the teachings of Buddha himself”.
Mahayana has not got a strong historical claim for representing the explicit teachings of the historical Buddha; its scriptures evince a gradual development of doctrines over several hundred years. However, the basic concepts of Mahayana, such as the bodhisattva ethic, emptiness (sunyata), and the recognition of a distinction between buddhahood and arhatship as spiritual ideals, are known from the earliest sources available in the Pali canon. This suggests that Mahayana was not simply an accretion of fabricated doctrines, as it is sometimes accused of being, but has a strong connection with the teachings of Buddha himself. Mahayana sutras - Wikipedia
At least conceptually, Mahayana Buddhism can trace itself to the historical Buddha, much like how a large tree began with a small seed that grew over time.
I think several aspects must be factored in- writing the same old hacked version is not going to get an author published. So there is pressure to come across a controversial view point and any view point can justified in an article with judicious use of selected facts. Also authors with a different religious persuasion might seek to undermine the Buddhist texts. I have heard of Christians who have a doctorate in Nirodhasamapatti, and the arms of church reach far.
Some are like this. But think of the many suttas in the Connected Discourses and Numerical Discourses that are just tedious lists or single unadorned teachings with no more narrative than a couple of proper names, presented in slightly different forms.
The earlier portions of the Middle Length Discourses are also rich, teaching-heavy texts in which nothing of note happens. This is clearly not predominantly a court literature designed to entertain people with stirring heroic deeds, adventures, romantic imbroglios or even edifying simple morality stories. A few exceptions, like the Angulimala Sutta, stand out by their contrast with the rest.
We live in a time where we are able to compare the Pali texts with the Chinese agamas, Tibetan texts, Sanskrit fragments, etc. to get a much clearer picture of what the Buddha might have said and to gain confidence in the teachings. For instance, the Majjima nikaya has about 152 suttas but has between 300 and 400 known parallels! To be beholden to one version of a sutta or sutra over another doesn’t serve us well, but rather limits our view.
This can be contrasted with Mahayana texts like the Lotus Sutra, Vimalakirti Sutra, Flower Ornament Sutra, etc., which are well-loved for their stories and parables. Rather than dwelling on whether or not these are historical narratives, I instead read them for their spiritual and instructional value.
The Buddha asked these to be specifically memorised not because they were memorable but because they were instructions which would benefit the person memorising them and allowing them to be transmitted down the ages. They are not meant to be read like reading a good novel
While there are no written records from the Buddha’s own lifetime around today, we should keep in mind that ancient India was an oral culture, and important religious texts like the Rigveda were faithfully passed down for hundreds of years before taking written form.
The New Testament gospels were written by anonymous authors, decades after the events described, and contradict each other on their accounts of Christianity’s most extraordinary claims, such as the resurrection of Christ:
From a historical perspective, it might be blind faith that would lead a person to believe that something like the resurrection is true, especially if extraordinary claims indeed require extraordinary evidence.
Buddhism is different in the sense that its central claim as a religion, the enlightenment experience of the Buddha, can be confirmed in one’s own personal experience by practicing his teachings, rather than depending on blind faith.
Not to mention that Buddhist texts (especially Mahayana) have all sorts of supranormal claims about deities and so on. In some traditions, these supranormal beings are hypostasized as central to Buddhist practice.
I prefer to focus on the problem of suffering and use that as the central criteria. If a claim in the text I am reading doesn’t seem to have a direct import to the experience of suffering in my life (32 marks of a great man, celestial bodhisattvas, etc), I just put it aside.
This makes reading the suttas much less annoying for me at the moment.