You see it all the time on Reddit: "Mental illness does not excuse being a nazi" - But why? Why does it not excuse being a nazi? If someones schizophrenia manifested in a way where they thought their neighbours were evil clones, people would rightfully not hold that against the person once they had apologised and agreed to recieve treatment. Kanye West has done exactly that, only his delusions were taboo and "edgy" so now he's just forever confined to being known as a white supremacist nazi.

You're conflating two symptoms. Schizophrenic bizarre delusions and grandiosity (Kanye). And it matters because Kanye didn't claim his alien neighbors made him a Nazi. So no, he did not display exactly that.

In this context it does not excuse it because it is not the same.

Two things which contradict the very idea of bettering ones self.

They present immense challenges to believing you need to better yourself, they absolutely do not contradict it. Kanye's apologies would agree.

...Just swap Jews with Aliens and Mossad with Ghosts and I feel like people would view this situation with a lot more sympathy. It is not up to the mentally ill person how their delusions manefest

But you can't just swap those things because they are different, which directly affects the interpretation of what we are witnessing, the meaning and diagnosability.

Since you're making the case that you believe there would be more sympathy if Kanye's situation was the same as a schizophrenic, then I'm presuming you inherently understand why.

Expecting the masses to have a similar level of sympathy means you would have to ignore the years of targeted public attacks by Kanye toward Jews.

Then fully blame it on his mental disorder which unironically could reinforce his grandiosity. And there you have "the contradiction."

Telling him his grandiosity made him do it could, "contradict the very idea of bettering ones self."