It may very well be a wider discussion, however the thread title specifically talks about Chris Huhnes' son.
It is as wrong an insult as saying that someone is a "retard" "spastic" "mong" etc... awful, horrible insults based on fear and ignorance.
Hecate I've got two boys with Autism, and I identify with you absolutely! I also find it very hard that there are people who think that they can just self-diagnose. Autism is becoming the "bad back" of this generation and I hate it because it makes a mockery of the soul-destroying, heartbreaking reality of getting a diagnosis and then living and fearing for an uncertain future. (Anyway... I've gone off on a tangent)
If you just take the OP at face value, however - I think it is, in this instance a forgivable offence and I have no doubt whatsoever that the lad is ashamed and incredibly remorseful. He did not know that what he thought was a private conversation was going to be plastered all over the media and discussed on Mumsnet! I, personally did a lot of things that I'm not proud of when I was 18... and I'd hate for those to have been done in the public eye and judgement of everybody.