I think an autistic classmate of mine is an asshole.
Why do you think that student is an asshole?
He's an inconsiderate prick. He's getting better grades than me even though he has a disability.
Just because a classmate is doing better than you are academically does not give you the right to call them rude names and think less of them because of their disability. That is being jealous and petty and it is inappropriate behavior. Instead of being jealous of another classmate's academic success, you should focus on yourself and try to do better academically if it is something important to you.
Calling him names makes me feel better about the situation.
You're being unfair. You're only calling him rude names because you're jealous of the success he's had. You should deal with your jealousy instead of being angry at him.