You do WHAT!!!!

[TeslaJr]

Look at it like this: if the bouncer had attacked your average person with his 1d6 damage club, and the bouncer had at least 12 strength (hey, he's a bouncer), then the average person (Commoner 1, AC 10, 2hp) would be lying on the ground bleeding to death.

If he had taken the -4 penalty to do nonlethal, or attacked with a sap or his fists or something? Yeah, he'd just knock the guy out for a few hours. Using a club like he was apparently doing? The guy he hit is probably going to die within a minute without direct medical care.

The only reason his actions were justifiable was because he was attacking a PC and thus probably wouldn't kill them in one hit (I say probably, since a critical hit would still do an average of 9 damage).

This wasn't exactly a case of disproportionate response.

In DnD, anything involving a PC is a disproportionate response. And the difference between your average commoner in a bar and a PC in a bar is pretty obvious (unless the PC was disguised or something), so it's not like the bouncer got confused. He used the right amount of force necessary to deal with someone as dangerous as an adventurer.