It is not fit to take delight in is what is meant.
It ought not be relished, is impermanent, it disintegrares, it is not self and is therefore dukkha.
The burning can be explained in analogical terms as a burning house, you shouldn’t enter and make it your residence.
The human state has been relished much and is entered upon by one with craving but this human state and existence in general, is a truth of suffering, it is only intended upon due to ignorance of not knowing better or not knowing a better.
If there was no escape from that which is impermanent then the highest conditioned pleasure would be a pleasure in a definitive sense; but because there is an escape from the conditioned, because there is a truth of extinguishment, therefore the highest conditioned pleasure is classified as a suffering & a calamity. It is burning, don’t wish for it.
Therefore eye and all is unpleasant, is burning & not fit to take delight, not fit for taking up as a hot iron ball and only the extinguishment of the conditioned is pleasant in a definitive sense.
It’s similar to this
Magandiya, suppose that there was a leper covered with sores and infections, devoured by worms, picking the scabs off the openings of his wounds with his nails, cauterizing his body over a pit of glowing embers. His friends, companions, & relatives would take him to a doctor. The doctor would concoct medicine for him, and thanks to the medicine he would be cured of his leprosy: well & happy, free, master of himself, going wherever he liked. Then suppose two strong men, having grabbed him with their arms, were to drag him to a pit of glowing embers. What do you think? Wouldn’t he twist his body this way & that?"
“Yes, master Gotama. Why is that? The fire is painful to the touch, very hot & scorching.”
“Now what do you think, Magandiya? Is the fire painful to the touch, very hot & scorching, only now, or was it also that way before?”
“Both now & before is it painful to the touch, very hot & scorching, master Gotama. It’s just that when the man was a leper covered with sores and infections, devoured by worms, picking the scabs off the openings of his wounds with his nails, his faculties were impaired, which was why, even though the fire was actually painful to the touch, he had the skewed perception of ‘pleasant.’”
The eye is a sign and a product of greed, anger & delusion, it is born of it and doesn’t originate without these. One can say delusion fuels the burning in this sense.