What would be his ulterior motive? there's no money in it for him; ivermectin is dirt cheap and he doesn't produce it. If you think it is all reputational, then it would have been easier and better to salvage his reputation by just admitting his educated guess was wrong if it is in fact wrong, but more research was necessary to prove that. No one would fault him for that, and he knows that.

I think he is just sincerely convinced by the evidence and wants to help tackle the pandemic. He made multiple recommendations some of which got adopted as standard of care (ivermectin wasn't adopted), before any good research was done, simply because that was the best that could be done in a new pandemic. He has got a pretty good track record, even discounting ivermectin

Then again, there are also studies designed to undermine the evidence for off label treatments, such as the one about HCQ that was retracted from the Lancet. So if you are gonna question people's motives then at least question both sides. resistance to ivermectin may also be unscientific in nature. Pharma companies have a lot more riding on mass vaccination than Kory has on ivermectin