Here is my theory on why there’s always been mass discrimination, or why people go along with the majority.
First of all even the most logical people are occasionally guilty of making decisions based on emotion, and these people justify it by twisting their emotional responses into what seems logical. So one influential person comes along and appeals to people’s emotions on how we should only eat chocolate cake and that eating vanilla cake is a sin. Now a few people will go along with, but there’s still a lot of people going what the fuck? So the leader and his followers keep pushing that eating vanilla cake is a sin. Now if the leader is skilled enough he will twist his ideas in to a sort of logic and bring in more followers (perhaps conducting "scientific" studies on how vanilla cake is worse for you then chocolate cake and will kill you faster). People don’t really question things that deeply. Ok so now there’s enough people anti-vanilla cake so they begin persecuting someone who is eating vanilla cake and the people still on the fence about the cake get scared and begin saying that vanilla cake is a sin, not because they truly believe but because they don’t want to be persecuted. Now there will be a sect of the population who aren't afraid of being persecuted but don’t want to be left out, and feel that socially they have to agree with the majority. And this is how mass opinions get formed. So not everyone agrees in the end, but at this point the overwhelming majority is on the side that vanilla cake is a sin. it doesn't matter or not if they actually believe it or not it's how their going to vote. out of fear, or genuine belief. Luckily the minority still has a chance as they just need to keep fighting back no matter what, and hopefully have on influential person on their side