No, neither reddit or lemmy are anti-American. Not even unamerican. It’s much, much worse: They’re non-American. Reddit by I think a small majority, lemmy much more so.
If, then, a random jingoist Seppo comes along and considers themselves and their dysfunctional country god’s gift to humanity, well, it’s easy to predict how much people will cheer that on.
Add to that another, equally exceptionalist, breed of Seppos, just that those don’t think the US is the greatest thing to ever grace humankind, but the worst. That’s not anti-American either, they’re still exceptionalist and they’re still Seppos. Hexbear and lemmygrad are full of them.
Also y’all don’t get what taking the piss entails.