It's the same social mechanism as religion. Go to a charismatic service and you'll see all sorts of shit, people babbling in made up languages claiming it's god speaking through them, can't reason with them obviously because there's no reasoning to be had. It's pure emotion. Feelings.

Humans have an innate need to do this sort of thing from time to time. How we are wired. Channel it in constructive directions, sports, church, temple, music, art, whatever and it can be quite good. Channeling it through activism usually just leads to a bunch people with poor grasps on the more academic arguments screaming really short stupid slogans.

Slogans with less 5 words and usually with a "to be" verb statement in them somewhere tend to be the most effective.

Trans rights are humans rights.

Meat is murder

Silence is violence

Love is love

Etc.

Not much to be said with slogans. People that use them and repeat them verbatim are essentially devout followers in a belief system from which they'll inoculate themselves against wrong think and doubts that creep in. You can't argue with a TRA that assumes anyone that takes any disagreement with them is in favor of literal genocide. Despite the fact that most everyone will agree with the basic idea that "trans people" should have the same rights as everyone else. They don't understand that the recognition of the legal distinction of "trans people" is the issue at play not their actual existence.

Political issues though are themselves usually fully wrapped up in this kind of emotional quasi-religious beliefs about "the issues" and it can be very very hard to get people to break from that and engage with the actual issues themselves and not the feel good slogans and hardline positions. Abortion is a great one for that. Try having a discussion on it with anyone and it will invariably devolve into philosophical disagreements of the nature of the soul which are of course impossible to reconcile. But in the public discourse you'll get the hardline anti-abortion people stick their head in the sand and pretend that medical complications don't happen and won't even discuss the possibility. Or go on the other side and hardline pro-choice people will refuse to awknoledge the potential of socially disruptive issues like, sex selective abortions, the ethics of choosing to abort children with deformaties or other abnormalities and the message that sends on their value to society. Etc. These aren't easy topics to breach. Most people are too intellectually lazy to think about them and just end up settling into a one size fits all approach towards them to save themselves the psychological trauma of actually having to think through coherent arguments towards positions like, why is it not ok to euthanize children with disabilities, but aborting undesirables should be allowed with no restrictions.

Or the uncomfortable reality of racial statistics when it comes to abortions.