Yeah, man. And why do all those scientists keep working on pointless things that aren't a cure for cancer?
Because any place that is designated as a "gun-free zone" thereby becomes a place of danger. Nowdays they are refered to as "Rob Me zones".
Generally speaking, bars are rather filled with people, so robbing people inside is impractical and a bit silly of an idea even when everyone is supposed to be disarmed.
Robbing them in the parking lot is a possibility -- bars seem to attract crime of all sorts -- but the typical target you want to mug is someone who can't defend themselves. For a bar, that most likely means drunk people, who would be in no condition to defend themselves if they did have a gun; you'd just end up with an escalation of the situation that would most likely work against the armed patron by encouraging the mugger to attack while the patron attempts to draw.
On the other hand, the threat of impulsive, alcohol-fueled murders in a flash of anger is massively increased when you let someone carry a weapon into a bar. 50% of all murders are committed under the influence of alcohol. Allowing guns into bars is a recipe for raising the local homicide rate.
Just look at what happened to the schools !
Over 99% of schools will never have a school shooting throughout their lifespan. There were 38 school shootings in 2000-2010 resulting in the deaths of 33 victims (not including the shooter). This number does not include colleges but does include a handful of non-public schools. There are just under 99,000 schools in America, meaning that around 4% of 1% of schools had a shooting, and of those most were single-target attacks or very short opportunistic attacks rather than the slow, deliberate Columbine or Virginia Tech style massacre that people hold up as an example of where a gun might help.
On the other hand, 606 people died of firearms accidents and 19,392 people died of suicide just in 2010 alone. So with that in mind, what exactly do you think would have been solved by bringing guns to a building filled with curious children and emotionally wrought teens other than a lot of opportunities for tragedy.
You have to do a fair threat evaluation. Guns in schools are a far bigger threat than they are a threat neutralizer.
On the other hand, I would exercise self-restraint and not go to bars full of guns.
Kind of like avoiding smoking in bars, you may find that the choice simply becomes "don't go to bars." On the other hand, you can tell a smoky bar upon stepping in the door, so those are easy enough to avoid. However, with concealed carry laws, you have no idea if anyone is carrying while drunk until it has become a situation unless the bar has a very clear sign on the door.
If you wish to live in community that heavily regulates firearms, then band together and do so - nothing restricts a locality/city/region from banning the things of their own initiative (see also Chicago, D.C, New York City, etc.) However, please do not try to impose such things across the whole nation. There is no "reasonable" restriction in the eyes of those who wish to promulgate these laws, save for complete abolition.
Due to a number of court challenges, there is no local governments that are allowed to practice such restrictions anymore, because "there is no 'reasonable' restriction in the eyes of those who wish to [oppose] these laws, save for complete [legalization]." See Heller vs. DC, et al.
Okay, maybe that's a bit too far. Most gun-enthusiasts support restrictions on felons and the mentally ill owning guns, but there are a good number of true gun-nuts that don't, and politics over the last decade has pushed further and further to the fringe on the right. Witness the latest law in right-leaning Georgia to allow concealed carry in bars where people will be intoxicated while armed.
I mean, why did anyone think that was a good idea?
"Experience has proved that some people indeed know everything." -- Russell Baker