> that the USA has mitigated it all, because that’s easily disproved by speaking to any minority person.

The OP literally said "It’s not perfect, but we strive in the right direction" in the next sentence

The claim that the US is not perfect and the claim that it is far less racist than the rest of the world are very very different.

I don’t see why that is the case, other than the fact that you disagree with the second sentence and not the first. Doesn’t make the sentences logically incompatible.

I didn't say that they are logically incompatible.

If Henry the Eighth said "I am not perfect, but I have treated my wives far better than anyone else in the world", then the admission that he is not perfect should not be sufficient to dismiss factual challenges to the second part of the claim.

They are just different claims. Which is what the Op was getting at.

Does the US have to be better than the rest of the world? All counties, everywhere?

This isn't really even allowing for equality with say Canada.

I'm only 25% down the comment thread, but so far not one commenter (including your parent) has said the USA has mitigated it all.

It’s important to read the phrasing and implications, than look for the literal “we’ve solved it all”. I’d quoted the relevant portions in my comment, if you think their phrasing is perfectly logical, so be it.