> Swear words and insults work because they break a taboo. If you regulate language to avoid one taboo, then speakers will simply resort to breaking another taboo.

I agree with this indeed, but I stand my point: the use of the word "retarded" is by all mean used to compare someone to a person with intellectual disability. I don't know the Dutch nuances of _Kankerlijer_ so I can probably wrong but I wouldn't think that it is used to compare one person to someone with cancer. What would that ever mean? "Retarded" it is used to compare, and it means that I consider you a lesser person just like an intellectually disabled one.