"Whataboutism or whataboutery (as in 'what about…?') is a variant of the tu quoque logical fallacy, which attempts to discredit an opponent's position by charging hypocrisy without directly refuting or disproving the argument." [1]

It's a logical fallacy (a form of ad hominem [2]) that doesn't do anything productive in re: the topic at hand.

[1] https://en.wikipedia.org/wiki/Whataboutism

[2] https://en.wikipedia.org/wiki/Tu_quoque