Who says so? What has been your personal experience with "the transgender community"? If you're seeing it through the polarized lens of online (specifically big platforms) interaction, then for sure you are seeing it as intolerant. But the same could be said about almost every pov online: most of what we get to see widely is vocal, shallow, unsubstantiated takes. Because that's what get viral.
So for one, there is no such thing as a "transgender community". There are most surely publicized simplified canons of what a transgender person is like, just like there is for "the average white dude", "the academic leftist", "the trump fan" or "the new age craftsy person". The thing is, there are very few person actually like that and the one that are, are usually like that because of tremendous influence of online platforms on their views.
All in all, with all respect, i think you are fighting a strawman. Personally, my course of action in this matter (shallowness, simplifications and argumentative intolerance getting more widespread) is not to fight against it for people you disagree with, because they for sure won't listen to you, but to fight against it for people you actually agree with. This is the thing: in every of these "communities" you describe (transgender, religious, could be anything) there is actually little internal cohesion and there are different political ideals interacting. I prefer to put my own house in order. In fact that's the only thing i can meaningfully impact.