it get that they're both bad faith ways to shut down discourse and i can see how whataboutism fits; but i was referring to the false equivalency placed between the nato's atrocities and that of the soviet union's in the comment

when it's "both sides" is brought up to shutdown arguments that the democrats have done some of the same things that the republicans did; they're likewise implying that the democrats have fewer of such incidents than the republicans and therefore the argument is invalid.

this was my half snarky way of saying that this comment is a "both sides" example can be applied in the opposite direction where it neuters the effect that "both sides" has with liberals.

I would submit that sometimes "whataboutism" can be related to the issue of topicality in a debate, though. If not addressed properly topicality issues will inevitably derail a discussion as is their nature.