Read the wiki on biotics, it explains the prejudices quite well.
As for why we never experienced it in game, I suppose in andromeda where Cora had hidden her abilities from the others is proof that there is still prejudices out there.
As for the trilogy, I suppose we don’t recognise the prejudices as most of the places we explore are mixed colonies and not predominantly human colonies.
Also I think that most of the problems were with early L2’s as civilian firms were funding the projects and probably releasing a load of Jack’s back into society with powers to do as they see fit. You can imagine how much some people would have abused these powers to begin with. Then there’s the obvious, how do you keep biotics in check without breaking any human rights laws? It probably would’ve been a massive transition and political agenda all over earth, some for and some against. With the way politics are now with their agendas you could really imagine how it would be if biotics actually did start getting released into society. It would be a mess, when in the end I think, where we met the biotic terrorists and chancellor burns, it’s apparent that the politicians just forgot they were talking about human beings that had been damaged with experimental drugs and implants.