I disagree with a decent amount of what the right has to say policy-wise, but I'd rather interact with them regardless, they're far less deranged.
This, flipped, was me with SSC. One of the few places you could hold a decently-rational discourse. Did I fit in? Hell no. Did I get called out on things? Hell yes. But it was people actually picking out faults in my arguments, or narrowing down to differences in underlying values. Not namecalling and social shaming.
RIP SSC :-(
This should definitely have been done after the first shooting
Yes.
if not before then.
I'm torn on this... but no. This is impossible to impartially enforce, and impossible to codify in a method that has a high enough activation energy to avoid being slippery-sloped. Selective enforcement of rules is a brutal weapon.
Dupe comment.
Slate Star Codex is/was a blog, though that description doesn't do it justice.
If you follow the link you'll find a much better description of what happened to it than I could provide.
/r/slatestarcodex (and r/TheMotte) are both subs centered around the SSC community.