I find it difficult to believe that any keeper would spend hundreds of dollars on mature, healthy animals just to feed them off when perfectly normal, inexpensive animals of the same species are available. IF that's true, then that person has way more money than sense.
The truth is very likely that he gets frozen feeders in from breeders who have had animals die off. A dead pied is not worth any more than a dead normal.
Now....if he's posting pictures like that just to get a rise out of ball python fans, that's another matter entirely. If he is implying (or outright stating) that he paid full retail price for those animals just to feed them to his cobra....then he's not only a jerk, but a dishonest, lying jerk (in all likelihood).
I've got no beef with people feeding their carnivorous, predatory animals with the closest animals to natural prey they're able to get. That means snakes for king cobras....and with the prevalence of ball pythons in the pet trade, and the relatively large size of them for older cobras, it makes a lot of sense that they'd be a good source of food. But I think ANYone who claims to love and respect animals/reptiles/snakes and then turns around and mocks an entire group of like-minded enthusiasts just because they enjoy one particular species.....well, that person is no true lover of animals, I believe. They are most likely in it for the novelty and because it makes them somehow "special" and able to brag about the "big, dangerous" pet they have.
Let me clarify one thing though....I don't have a problem with folks who playfully make fun of the ball python craze. That's something else entirely. I just mean the people who deliberately set out to cause strife and try to make others feel crappy because they happen to like something different.