These answers sound like they are coming from a lawyer defending the referee. They are very informative and clearly grounded in experience. But I'd really like to know what you you would have done. Red card or nothing?
I would look at the reaction of players. If no one reacts I wouldn't do anything, whereas if it provokes a response I would send off safe in the knowledge that I would be 100% backed by the authorities.
If I spoke to the offender or pulled a yellow card on him I know I would be putting myself at serious risk, so I wouldn't do it.