I'm familiar with its origins. My feeling is: I used the word accurately.

"The tactic behind whataboutism has been around for a long time. Rhetoricians generally consider it to be a form of tu quoque, which means "you too" in Latin and involves charging your accuser with whatever it is you've just been accused of rather than refuting the truth of the accusation made against you. Tu quoque is considered to be a logical fallacy, because whether or not the original accuser is likewise guilty of an offense has no bearing on the truth value of the original accusation.

Whataboutism adds a twist to tu quoque by directing its energies into establishing an equivalence between two or more disparate actions...

The association of whataboutism with the Soviet Union began during the Cold War. As the regimes of Josef Stalin and his successors were criticized by the West for human rights atrocities, the Soviet propaganda machine would be ready with a comeback alleging atrocities of equal reprehensibility for which the West was guilty."