Saying "I know a mentally retarded person" is liable to attract flaming - it's like saying "I know a l3sbian" or "One of my friends is black"
Although a cliche, it's not the colour, shape, ability but the person that should count. I mean how many people have you heard say "Yes, I have a friend who has long blonde hair" - so what!
Mind you, it questions WHY he was looking for those sorts of pictures. The orginal picture itself is amusing and is not making fun of the person shown given the context of the narrative, imho B)
<gets off soap box>no offence to anyone</gets of soap box>