It isn't a hateful slur, Retard.
Why? Because no one ever calls people who have down syndrome or other mental disabilities that word. That would be rude, though in some cases, apt.
Instead, we call functioning people who have a working brain and should know better, a retard.
Like you, you retard.
The R word need to be banned from X and society in general.
It's a hateful slur and anyone who uses it should be held accountable.