This bartender was trying to score points with the girls at this guy's expense as well as shut his game down. That's uncool and kind of cruel. At least the dude is trying. On the other hand, if the guy is harrassing the women and creeping them out, then that's a different story.
I go out alone nearly all the time out of necessity. Most guys my age are married, engaged, or have a girlfriend.
Plus, I've gotten used to not having a wingman and don't really want one anymore for the following reasons:
1. It's way too easy to talk to your wingman all night and not approach. I think we've all had that experience.
2. It's especially bad if your wing is REALLY picky with girls. You keep waiting for PERFECT 10s who never arrive and don't end up approaching anyone. At least if you are alone, you can approach any girl you are attracted to (even if she's fat lol) and you can't be judged.
2. Sometimes you are having a good night and your buddy is having a cr&ppy night or vice versa. Should you leave the club or stay?
3. Your wing likes and/or does well at a given club, but you hate that place and prefer another. Which one do you go to?
4. You feel like you're tag-teaming every set and ganging up on the girls by approaching with your wing.
5. Even if you meet a two-set, what are the odds of you hitting it off with girl 1 AND your wing hitting it off with girl 2 simultaneously? Very slim.
6. Competition. It's like Murphy's Law that the girl you are most interested in somehow is attracted to your wing, not you.
7. If your wing doesn't watch his mouth, he can get both of you dragged into a fight.
Of course, there are two sides to everything. There are downsides to going out solo like some posters have mentioned:
1. It is unbelievably hard if you are socially awkward and girls will judge you harsly for being alone unless you are very socially savy or have a REALLY GOOD excuse for being out alone such as you are waiting for a friend, you are in the city on business, etc.
2. You need to stick to classier, safer places since you have no wing to back you up if some guy gets hostile.
3. It can be very hard to extract a girl from any set. The girls don't want their friend to leave with a strange guy because they are concerned about her safety. This means your best targets are lone wolfs. However, most lone wolfs at bars and clubs are old cougars. Young hotties don't have the confidence to go out alone. The rare exception might be a business traveler woman at a hotel bar who is there alone because she's in town on business and felt more comfortable going to her hotel lounge than a local bar.