Earlier quoted context omitted.
Being offended is your problem, not his. Have we learned nothing in the last 24 hours?!
Many people find the word retard (used that way) to be deeply offensive. Many other people are not aware of that offence, and also would not like to cause that offence, and once they know that many people find the word so offensive are happy to consider their use of language and find another word. There are lots of great words to use instead of retard and retarded. And asking someone to consider their language isn't…
Seriously. Could you stop that please?