It's the internet in general, my lovely. It lacks nuance. And anything extreme, either side of the spectrum, rises to prominence. It's what people click on.
Yesterday I typed up a long nuanced post for some trans thread and then ended up just deleting it because I know nothing good would come of it. Someone might agree with 70% of my argument but grab hold of that one phrase that rubs them up the wrong way and release the vitriol.
You have the loud very polarised opinions, and then you have a large, moderate silent majority that just doesn't get involved in all the noise. These are the same sorts of people that might not bother to vote, or stand up for someone/ something, and hope it all works out for the best/ sensibility prevails. Sometimes it does, sometimes it also clearly doesn't.
Just speak to your actual friends and IRL people and don't let the internet cloud your world view, it's either an echo chamber, rage baiting or very polarised, because algorhitms, clicks, selling ads... You get my point. There's a reason why there's usually a trans themed post featured in 'top 5 trending' on here, why you see that content and why it's given you the impression that it has. Controversy sells.
Something you'll see a lot as well is that very educated and informed people rarely engage in these debates as they know they won't really be listened to and can't win, so why bother. (And by the way, these people could choose to argue either side)
Adam Rutherford makes rather good points on that.
Also, people that run Mumsnet have purposefully made it a safe space for anti trans views, it's part of the platform's positioning, so you'll see it more here than perhaps other similar spaces.