"Whataboutism" is trying to deflect to an utterly unrelated topic, like suddenly turning around, pointing at a tree an screaming "but what about the pine needle water content cartel?!".

It certainly isn't pointing out hypocrisy, establishing a common standard or a cureall in online discussions.

I've seen a proper "whataboutism" been used but only once (by a malfunctioning redditor from Eglin Airforce Base).