but I would prefer if people who get negative feedback learned from it, instead of organizing an upvote brigade.

Its more than this - if people don't realise that upvote brigades exist (probably using sockpuppets) then it gives the impression that a substantial proportion of LWers endorse mass murder.

It is not impossible to create another website that rationalists will read: see Slate Star Codex.

Also, Ozy's blog has unmoderated discussion where advocating genocide is ok, there's 'more right' etc.