(1) I am from $region_X and I went to $region_Y

(2) $region_Y'ers do things in a way I find unusual and/or distressing

(3) The cause must be a character flaw shared by all $region_Y'ers (<insert stereotypes of choice here>).

and your statement is still valid about this formula.

I think we tend to preferentially notice them when we're in one of the two regions involved, but in general the world (and so the internet) is full of this sort of semantically null comparisons about culture and stereotypes. I've started seeing these as idle chatter akin to "Hey, look at that weirdly painted bus". At most I'd respond with "oh heh cool" but I'm not going to spend any more of my energy trying to explain choices of bus colors to anyone.