I use the "ignore" feature on anyone who is rude and/or disrespectful to me.
I "ignore" anyone permanently who acts catty and passive-aggressive with me, and makes snide comments about me behind my back. I take a "zero tolerance" stance to that sort of thing.
Advocating extremist political stances which, if implemented, would lead to my death, is another ground for "ignoring" someone in my book.
Respect your own dignity. That's my motto. Life's too short to waste it on toxic interactions with people on the Internet.