My take on that is that America has broadly "tolerated" counter-culture movements that are chauvinist and either toothless (like hippies) or largely aligned with capital (like libertarians). They may still face repression, but they don't get the sort of complete institutional shut-out that communists get. The hippy movement came from that sort of tolerated counter-culture where however scandalous the mainstream may have found them they had at least some degree of support in academia, music, and hollywood, and was a highly-individualistic movement that replaced solidarity with nonsense mysticism and was concerned mostly with the personal liberation of its adherents from the restrictions of the world around them (and, as always, that went along with the chauvinist idea that personal liberation means the freedom to act however and on whomever one wishes, regardless of the desires, wellbeing, or rights of others).

I've talked before about how that sort of chauvinism dominated the American "left" up until relatively recently (spoiler: the turning point was gamergate and its related culture war bullshit) when the worst chauvinists split and got sucked into propaganda machine that sought to reconcile their self-interested chauvinism and desire for personal freedom to act however and on whomever they pleased with the previously rigid public-facing moral ideas of the far-right, creating a true fascist movement almost overnight, with the upside that in their absence/in reaction to this the left also started crystalizing and turning against that sort of chauvinism, leading to a resurgence of actual leftist ideology instead of just the "I sort of want healthcare, am ambivalent about LGBT rights, and find the theocratic far-right unsettling and bad" umbrella that previously defined the American "left." It's not enough, and there are still plenty of other sorts of chauvinists like vaushites and breadtubers muddying the waters, but it's better than it was twelve years ago, hence why the old institutional shut-out machines are starting to turn and the left is increasingly under attack again.