it's 'organic' to a certain degree
let me explain:
reddit staff is known for being very much pro tranny
reddit moderation team is known for being filled to the brim with tranny jannies
this creates a situation where "be nice to trannies, or else!" has become the law of reddit. part of it is unwritten law, part of it is openly stated in subreddit rules
so far this is all artificial and top down. but now we look at what effect such an environment has on the users?
first, those with anti tranny views either leave, get thrown out (banned) or keep their mouth shut on the issue. all have the same effect: expression of anti tranny views goes down a lot.
second, those with pro tranny views (trannies themselves and convinced leftists) are emboldened. they know that pro tranny views are officially supported and welcomed by the people who run the place. not only does this encourage more posting of pro tranny views, it also promotes these users aggressively attacking (both verbally and via downvote and report functions) any anti tranny post they might come across.
third, those with no strong opinion on the matter: they see that not a lot of anti tranny posts are made, so they assume anti tranny is a small minority position. they also see that anti tranny posts are frequently deleted and the posters banned, and they see that people dunking on anti tranny posters are encouraged. combined together this creates this view of the situation:
anti tranny = minority, powerless, outcast, criminalized, shunned
pro tranny = majority, powerful, accepted, promoted, encouraged
presented with that choice, near everyone will intuitively fall in line with the pro tranny line. this is organic, it's how people naturally act.