Well, there are people with various psychological ailments, or just as a matter of their personality, where they don't like to be touched by other people, much less hugged. The Washing variation of OCD, for example...

Oh. That was a rhetorical question.

The funny thing is I'm one of those people too :)

Which one? The ailement or the personality version?

Also, I thought of a few other people that don't want to be touched:
The queen of England, Queen Elizabeth II - unless she's touched first
The queen of Thailand, I think but I'm not sure
Most Arabs, if you touch them with your left hand
Temple Grandin, inventor of the hugbox (I don't think she likes being touched by people)
John Brown - he's moldering in the grave, and doesn't want hugs
Hitler - all that's left of him are a few bone fragments that survived his cremation, since he didn't want Stalin to get his slimey fingers on him

er, unless the Queen of England makes the first guesture, that is. As Michelle Obama found out. The queen is probably poisonous too.