The groups you cite are civil rights relevant. Do you think Rand Paul's thoughts are an expression of his religion or evidence of a handicap?

We make a distinction between characteristics/traits and actions, generally. It's generally wrong to discriminate based on traits and fine to discriminate on actions.

So; if YouTube said "we don't allow Christian white men" or whatever, absolutely, that's terrible and shouldn't be allowed. If they say "we don't allow people to say things that are actively harmful" that's quite different.

If you go into a restaurant and insult the servers, or start bothering other patrons, they'll ask you to leave. That's perfectly fine.

Mask opinions are not a protected class

Yes, if you're actually a libertarian -- like Rand Paul claims to be -- that is in fact fine. People can vote with their feet.

edit: typo