I was a bouncer for about 5 years during college. I worked for 3 brothers who owned like 7 rap clubs, including 3 of the largest in my city. I also worked at a small 20+ year old college bar in the nice area of the city.
In my experience, bouncers that start fights don't last long. It opens the business up to liability and lawsuits, so owners will fire bouncers that get into too many fights. Also, that's a great way to get yourself shot walking to your car. I've been shot at because a different bouncer roughed up some kid kicking him out. I've had a friend get shot in the chest (luckily small caliber round hit his cell phone. incredible luck) after another bouncer kicked a guy out. Another bouncer I knew was shot at by some Hispanic gangsters after choking one out. And a bouncer down the street from my bar was murdered by someone he got into a fight with. Fighting isn't fun when people die afterwards.
I've definitely gotten into my share of fights, but I really try to avoid them. For one, it's not my business. It's no skin off my back if someone needs to get kicked out. I learned quick to pass blame onto "management" and "ownership" when kicking someone out. I'm just the messenger. I'd always try to get them outside to "talk" before I let them know they couldn't come back in.