What kills startups is a flock of alt-right users who scare away people not like them (the xenophobia is definitional to "alt-right"), so if you let them stay a

What kills startups is a flock of alt-right users who scare away people not like them (the xenophobia is definitional to "alt-right"), so if you let them stay and don't hide them, you immediately cap your growth substantially. If you let them stay and do somehow hide them, you're hiding your growth which also kills you. A free market would (and does) kill a startup that allows such toxic members of any affiliation, regardless of what payment processors decide to do.