It's that the poster didn't give any supporting comment to their claim that a lot of [the idealogy that is being foisted on the minds?] is "even anti-American".

Claiming something is un-American is fine. We're (mostly?) red-blooded Americans here.

However, pointing at something and saying it's un-American and expecting the crowd to gasp in horror and join you in denouncing it, is a very clear signal of a Fox-news-or-something-deadened brain.