More often than not when I've seen "whataboutism" used here it means "You can't say that (about me), I said it (about you) first!" which is in my opinion, intellectually lazy. There are times when a bad faith whatabout-ist argument is made as a diversionary tactic and they are frustrating, but the original comment[0] we are discussing does not feel like that to me. In fact the comment they were replying to is making the lazy and intellectually lacking argument.

[0] = https://news.ycombinator.com/item?id=30579098