I don’t think crazy in a blank check to get away with whatever you want, you can definitely make yourself crazy in entirely foreseeable and avoidable ways that are your responsibility. This can still render you unreliable when it comes to your own motivations.
I would say, "yes," but this is crazy in some type of modern-day social sense of the term. If we're to consider the long, rich history of human violence it looks a bit pedestrian.
He's not a member of your tribe, your tribe attacks his tribe, he attacks yours.
He played by an older, darker, less civilized rule-book.
So he's not "seeing things schizo crazy" and so in some sense, no, he is not crazy.
I find virtually all mainstream discourse around mass-casualty attacks to be either normalizing or to just simply sweep the issue under the rug and ignore it.
There is no deep discussion on the topics, just further fiddling.
This is what a lot of people are afraid of in the US, because these shootings exist at the nexus of first and second amendment rights. The first allows people like the shooter to be radicalized using the most powerful communication platforms ever created. The second allows them to be armed to the teeth. And then there is the systemic, deeply rooted racism in American culture that feeds the hatred behind these events, and intersects with the US Constitution, government and society in numerous ways the country still isn't capable of discussing rationally.
So "he was just crazy" starts to sound like "nothing to see here" after a while. Because if it's true, it's weird that so many people seem to be crazy in the same way. If they aren't crazy then there is a pipeline of radicalization and violence - an "extremist industrial complex" if you will - that's working as intended to maintain its own status quo... and a lot of Americans are fine with that.