As Kimmy said, it’s about intent, which drives pretty much our entire criminal code.
Another way of looking at the same idea is that, in your example, there’s an aggravated sentencing condition based on the belief, but there are already plenty of actions that are classified as legal or illegal depending on the presence of certain beliefs or thoughts. In other words, it isn’t that clear of a distinction between “thoughts” and “crimes” as you might think at first blush.
Picking up a CD in a store - not a crime. Picking up a CD in a store with the intent to leave the store without paying for it - crime. Putting your hands on somebody’s shoulder - not a crime. Putting your hands on somebody’s shoulder with the intent to harm - crime. And so on. So if we can make non-criminal acts into criminal acts based on what’s in your head, why can’t we make an already criminal act a different kind of criminal act based on the same (assuming there’s evidence, I mean)?