That doesn’t make sense. If anything transphobia in society would make transitioning less likely to alleviate suffering. I basically agree with you that some people do it as a matter of preference (I’m frankly not sure what the numbers are), and I don’t have any real beef with that (as with any form of ‘body modification’ it’s simply up to the individual — although as in those cases, I don’t think I’d want children getting involved at a young age). I also find it tends to be bound up with mystifications about sex and gender, and isn’t purely e.g. an aesthetic decision, like other forms of body modification, cosmetic surgery etc. — in which case the mystifications are open to question.