flapsforty wrote a brilliant and very true post!
Unfortunately, it happens more and more often; when it happens to me (or anyone in my crew), after analyzing my options i tend to go by "better safe than sorry" - i started using this "motto" if you want after deciding not to off load one of these "abusers" and, just like flapsforty, we ended operating the flight from hell.
The commercial side of an offload (go back to the gate, delay a/c and so on - the a/c makes money in the air, never on the ground) is, sadly, a pressure to the flight crew and CC. However, I would say that in my airline, 99.9% of the CPs will support our decision to offload a pax and should the company turn around and question the offloads' costs, he/she will point out that the safety of the crew and pax have
NO cost.
Also, reports are being written and statements to the police given.
Some companies may take the offender (i really want to say idiot but I'll keep it formal...) to court and ask for him to pay the costs of the delay.
And again, as flapsforty mentioned, we are being trained to deal with an abusive pax; we (in my company) also had a self defense day course which did absolutely nothing for me, somehow i don't see myself fighting with one of these "abusers".
Self control, calm and quick thinking do it for me.
And it's not only on the ground when it happens; some might kick off inflight, and you can't really "go back to the gate"... If we don't manage to deal with it, the CP (who we keep informed at all times) might divert to the nearest airport, off load, police will arrest, company might ask for costs to be paid and so on (as above).
No matter when and where it happens, i think there are ways of dealing with it calmly; having said that, if it gets really bad, some other pax might get involved to try and help us (again, it happened to me).
these people are "abusing your uniform" rather than you
The best, and healthiest attitude one could ever have in a situation like this!