I’d rather not work for an employer that is or was so hostile that the employees needed to rise up

That sounds horrible. I have never seen nor heard about a situation like that (in a legal setting, illegal work conditions are another matter). I am also not from the USA (which I assume OP), so my perspective is perhaps different.

Joining a union is never forced where I live, and you can join a union without your work having an agreement with one (they will give legal aid, probably more, and try to improve all workers’ rights. A lot of benefits I enjoy today is because someone else took the fight before me).