In the western world, there is a tendency to jump into a fight to help the victim from getting beaten.
It is human nature to want to help (although these days 90% would probably just stand there and film the beat down.)
If you see a foreigner getting in a fight and beat up in Thailand, it is best to refrain from joining in.
It may be hard to stand there and watch, however, if you get involved to help a foreigner in a fight, Thai’s will rush in from everywhere and both of you will get beat up.
It is not uncommon for 10+ Thai’s to jump, even without knowing who/what starting the initial fight.
Thai men seem to have a hatred for foreigners beating up Thai people and they will take that hatred out on any foreigner that gets involved.
Once altercations turn to violence, there is not going to be a good ending.
The types of altercations always seem to be in tourist areas like Pattaya, Phuket, Bangkok.
Anywhere this is a high concentration of foreigners and beer.