There was one time I was trying to park a motorbike somewhere in the beach city of Ao Nang just to drop something off, I wasn't trying to leave the bike there for a long time. This was one of those self-declared taxi-ranks that you are talking about where they took control of it even though it is not theirs to claim. They ganged up on me and became very aggressive towards me even though I hadn't even turned the bike off, was still sitting on it, and I was speaking Thai to them and explaining that the bike would only be there for a few minutes. Logic didn't get through to them, they were being tribal and were having none of it.

While none of us can know I agree with your sentiment that there is very little chance in Pattaya that this taxi driver was just being a super nice puritan and the evil travelers just decided to beat up a stranger for no reason.