Have ever blocked everyone who has replied to one of your posts before?

Yep. Or rather the 2008, 2012, and 2016 US Presidential elections did that. Mostly though they blocked me. Their loss.

no but under the right circumstances I probably could

No, I haven't blocked everyone, usually add.

In the very beginning. yes.He was an asshole.

I can't even imagine that

Many! And I shall continue to do so!

Can't say I have.

Nope