So according to him, racists and conservatives make the workplace inhospitable for liberal people. That's fine, I understand racists can be bastards sometimes so I'm not debating that. What I'm debating is his solution.

Now I've observed what he did to a poor immigrant when he disagreed with how that immigrant may not see the world in the way he wants him to.

The immigrant was isolated by him and his associate liberal friends. Constantly ridiculed, and almost kept as a prisoner by them to only work in positions beneath them and not anything else. The guy kept begging for them to leave him alone but these losers kept suffocating him to the degrees that he became suicidal. Their ultimate aim was to get him sent to a mental institution and kept him imprisoned for the rest of his life by calling him schizophrenic. When I got this communicated to him secretly, he left the country and went back to his older life in a lot of problems.

So how is what they did any different?

They did something much worse. At least the racists are direct about ensuring they don't want you in their company.

Source- personal observation and experience