Over the past couple of years there has been a disturbing trend of young kids that decide that bringing a gun and spraying down their classmates and anyone else that happens to get in the way. Now remember I am talking strictly for college not high school Why because most of the time HS kids can't legally own a gun.
I think that you should, be able to bring a fire arm onto a college campus, if you do certain things first.
1. Have a concealed weapons permit
2. Inform the college that you will be carrying a weapon on campus. And get a permit which to get you must take another stricter course in firearm safety.
3. Only be able to use it under very strict guidelines. Only when you face imminent death.

Your question is why should these irresponsible kids be allowed to bring guns onto a college campus? Because the colleges of America have shown us over and over again that a individual with a variety of legal firearms can illegally and very easily bring them onto a college campus and kill, mane, and wound many many of his/her unarmed classmates or fellow humans before the college police or any police force can mobilize.
The colleges are for the most part unable to properly defend their students from attacks and can not guarantee their safety. If the colleges could promise you that if a gunman would not make it far on that campus then I would feel safe leaving my firearm at my house. Until that day, I want to be able to "stay strap" because I don't know you, or what kind of weirdo you are.
But in all the school shooting that I know of, the shooters for the most part committed suicide, after leaving their deadly trail of destruction and the police simply helped the coroner carry out the bodies.
The reason for this is that yes there is a chance more school shooting will happen. But answer this question first, what would you rather have, two people get into a argument, break the rules and both pull guns and someone gets shot. Yes that is sad, but what is more sad is a lone gunman walking into a room and shooting 24 unarmed people.
I can honestly say that I would rather die by getting shot and at least having the ability to fire back rather than die by being shot while I am hiding under a desk because I can't bring a butter knife to school with me. Where are the police officers? Waiting out side yelling into a mike they got the place surrounded, waiting for the gun shots to stop so they can go in...
I believe that we have a right to feel safe, if not we should be able to have a weapon to defend yourself in a time of crisis. The schools of America have not done the job of protecting the students. Like after hurricane Katrina. The city of N.O. asked for citizens to turn in their guns. The police then left the people to the mercy of the mobs and gangs who didn't turn in their guns. The police force did not have the man power to defend the law abiding citizens. Same is here, the schools ask us to not brings guns into a college campus, then don't have the means to defend against a imminent attack, and I say imminent because I am sure that another person will try it. After that they want to hold a candle light because 20 plus people died because they purposely placed you into a situation, refused you the right to defend yourself then purposely didn't properly defend you either.
I think that there will be more shooting, but at the end of the day its about whether you die fighting back or under a desk because the authorities refuse you both protection and the means to defend yourself. In recap, yes some people will get through the system, there are bad apples no matter how hard you try, but with the proper application process and special classes that are further in depth and tighter restrictions on when it is appropriate to use your weapon, I think that we can feel much safer.