I find that liberals are much more dismissive of US atrocities. Most communists I speak to know a wealth of details about the failings of mao and stalin.

Ask a US conservative about our 20th and 21st century atrocities - torture, massacres, coups, support for genocidal regimes and ecocidal companies, etc. - and they'll proudly defend our brutality. Ask a liberal and they'll hedge, deny and justify like an internet tankie who's never opened a history book.

That hasn't been my experience at all. Sure, there are nationalists who will defend their own favorite Communist^(TM) Regime, but an ideological believer in communism is just that.

every “communist” when pushed will take position on atrocities committed by various communists regimes… they gonna do that thing that “fascists” do: “well he really did not do it but if he did, they clearly deserved it”

I have never encountered that argument. Is that something Tankies say?
What I have seen is the often mocked argument, that these regimes were not communist in the first place.
Actual communism has never existed and probably never will.
There are however plenty of communists that will openly denounce stalinism. That is the entire premise of Animal Farm, btw.