While I think that Sean's behaviour can sometimes be pretty not helpful (or even toxic), I have to say it is *very* pretentious to consider him "harmful for the JS community".
Besides the original Twitter thread (and some others I've read now and then) he's generally a very supportive member of the community. Also sadly — even if this does not excuse any concrete behaviour — I've very rarely met people as passionate and as charismatic as him who didn't have a tad of a choleric vein.