Ahh, but if we don’t? (It’s a difficult passage, and I’ll be posting an essay on it soon.)
This is a kind of language that some scholars are apt to use, but to my mind it’s a misleading imposition. Anxiety is where you feel a degree of internal stress and turmoil, and that has nothing to do with this passage. Sometimes, I agree, there is a persistent worrying at a point, so that the issue is ever bounced around and never quite resolved, such as the question of the bodhisatta’s leaving his wife and child behind. But that is not the case here. To treat every qualification as “anxiety” is too blunt an instrument.
This passage making a subtle distinction in the roles played by extremely elevated meditation states. It’s like saying that if a physicist says that “noble gasses are defined by their lack of reactivity in normal conditions, except for certain cases involving xenon”, then they have “a kind of anxiety” about xenon and whether it is really a noble gas. It’s not anxiety, it’s an understanding that there is nuance and complexity in the world, and that simple generalizations made in one place sometimes have to be qualified when looked at more closely.
You’re making all kinds of assumptions based on a particular idea of what brahmins were. The theory of atman is by no means fundamental to brahmanism. It was a philosophical speculation that developed among certain of the contemplative and reflective members of the community not long before the Buddha. Most of the things brahmins believed and did were to do with sacrifice, recitation, caste, the gods, and so on, none of which really has anything to do with the atman. So far as I know, atman doesn’t even occur in its philosophical sense in the Vedas, which are overwhelmingly the brahmanical text of reference for the suttas. Some of the texts aimed at brahmins in the suttas discuss the atman theory, others don’t.