Whataboutism-style rhetoric can contain valid points, which makes it all the more frustrating. If it didn't, I could just ignore it as propaganda from the ideologically committed. I guess it's just too much to ask for people to bring up their valid points in a way that doesn't intentionally derail conversations on often orthogonal topics.

Also note that if an opinion is almost perfectly correlated with a nationality, that is a reasonable cue to question its rationality.