You said the other commenter’s point seemed to be ‘because America did bad things we must let bad things happen’. That wasn’t their point, at least not to my reading of it. I read it as trying to highlight the hypocrisy of the international community, which usually means the USA and associated countries.
None of this is to excuse the war in Ukraine, but if the international community is to mean anything, and to have any legitimacy, it needs to apply the rules across the board. Since it doesn’t mean anything beyond what is good for the US/corporate interests, the rules have not, and will not be applied evenly.
The US is not trying to do the right thing, it is trying to advance it’s interests in the region at the expense of Russia, and unfortunately for Ukrainians at the expense of them too, even if it benefits Ukraine as a state. The fact that the US can wage so many destructive wars that are later acknowledged as mistakes and still be seen as trying to do the right thing shows how effective the propaganda arm of the country is.