A lot of Chomsky's interviews or the ones I've seen deal with how freedom of speech is above everything, how violently opposing war is irresponsible, how the best way is to talk it out and put the responsible ghouls in charge.
He demeans the violent demonstration against the invasion of Vietnam.
It's the same with reformists that try to redirect the anger and indignation into impotent ballots
He can proclaim be against war but if he bashes those who oppose it through any kind of disruption, I will still call him someone that perpetuates the empire
Edit: it's early in the morning and I'm rambling so I'll probably elaborate latter during the day
Leftism is such a purposely nebulous term, as long as you have one slightly decent take you are a leftist, if you think that a broken arm shouldn't force you to declare bankruptcy then you are a leftist even if you are pro invasion, same with pro LGBT right but you are a mouth foaming racist, see Bernie Sanders