Sure, merelly saying “whataboutism” is often used as you describe, mainly because like so many other words its meaning has been seriously mangled through misuse.

It does, however, make sense to ponder on the logic of pulling something wholly unrelated to the actual situation being discussed and posting it: since such “arguments” by association do not make sense in that context, it’s logical for those on the other side to then consider further elements seeking a reason until finding one that does make sense, which is typically an attempt at holding a position in a discussion after having exhausted actual logical arguments, something which itself would indiciate that the person using such “arguments” doesn’t really hold that position on logic.

You don’t need to label it as “whataboutism” to recognized an argument by association as the falacy it is, it’s just that using the word “whataboutism” is (or, maybe, used to be) a good shortcut instead of all the text above I just used to explain the rationalle behind the use of the argument by association falacy.