I don't agree that what you're describing is whataboutery. What I understand from what you wrote is that you're talking about bringing up another instance of a similar thing as part of the same discussion.
The rhetoric of bringing up the USA's invasion of Iraq in response to criticism of Russia's invasion of Ukraine certainly hasn't been to support criticism of Russia, it has been to say, "but the US did it, so it's not so bad when Russia does it".