“...traces the aforementioned undeniable truth, that the arc of American politics has moved in his direction, thanks in large part to activism.”

Huh? The acceptance of American imperialism, militarism, corporatism is ubiquitous now. The acceptance of more authoritarianism is everywhere - distinguished between groups mostly by what form it should take and how it should be implemented/achieved. I really don’t see how the arc of American politics can be seen to have moved toward Chomsky. There really is no old-school “left” anymore - the opposition to both political and corporate power - and what social causes of the old left that have made progress are now taken up by the new “left” as a means of control (perhaps most noticeably and acutely in the whole current manifestation of identity politics).