No one is locking trans people away or saying they can't live happy fulfilling lives. And I don't think society is reacting to the condition - whatever the condition may be. (I actually think it's a range of sometimes overlapping conditions including internalised homophobia, AGP, not fitting in for various reasons, trauma, and social contagion. Being "trans" can have very different forces behind it for different sexes and ages.)
What pisses people off is not that some people may have a particular condition, but the overreach in saying that means they ARE the sex they are not and must be treated as such. It's ridiculous, harmful to women and children, and harmful to the social contract and the general consensus that we're allowed to challenge untruth and it's normal to feel discomfort about lies and being forced to lie.
It doesn't actually matter in this regard, if it is some kind of real neurodivergence or not. Whether you have a real, testable brain condition that makes you wish to be the opposite sex, or it's a fetish, or a way to get cool points, or a plain old lie to get predatory access to women or a more lenient sentence - none of these mean you are the opposite sex in any way, and no one should be categorised as the opposite sex in situations where it matters - like changing rooms, prisons, hospital wards, sports, toilets, breastfeeding groups, anywhere where single sex facilities are there in the first place for privacy, dignity, fairness and/or safety, and certainly not tolerated forcing their way into homosexual groups or apps or meet-ups when they are not the right sex for that group.
If some people have a brain condition then that's hard for them but newsflash, lots of people have conditions that make life harder or dearly wish they could be something they're not. No one else gets special treatment.
As I've said before I think trans should literally means transgender - you wish to present in what you perceive as the gender expression of the opposite sex. Fine, people have been rejecting gender stereotypes forever, and probably 99% of people don't actually fit strictly into a gendered box anyway. I can also get on board with such people having standard equalities protections, as long as they're subject to the same expectations of decency as everyone else (no bollocks dangling out of tiny miniskirts when that kind of self-exposure wouldn't be OK for others). But no one is somehow magically not the sex they are and it's time sanity prevailed and everyone can stop pretending.