So you don't bother to google and check if the Ukraine has a habit of lying too, and prefer to believe anything coming from Kiev only because Russia says the opposite.

The word 'whataboutism' is a form of dishonest debate and used to distract from critique of double standards.

"guess who invented it? russia, of course."

I'd say it was invented during Cold War by some American in search of rhetorical device to distract from their double standards.