I hate mentally disabled people
Why do you hate them?
They are such a pain.
Writing someone off just because they have a mental disability is not all that fair. Understand that these are people too, and they have many other characteristics aside from the mental disability.
Nope, I've moved on.
Well, if you're still here, I have to reiterate that you shouldn't hate people with disabilities, even if they cause inconvenience for you.  Just think about how difficult life is for them every single day, and you should realize that you can spare a little extra time and effort to accommodate them.