Actually they do. My property rights trump your self defense rights. You don't need to be on my property. You don't need to go to college, don't even have a right to. You see where I'm going here? Your employer can ban guns in the workplace if they so desire. You can either carry and be fired, quit, or not carry. You can't take them to court to force them to allow you to carry. Unless they're a state or local agency, and your state has preemption laws that work in your favor and don't prohibit in the state agency you happen to work at whch is so narrow and unlikely to fall exactly into place that its not really worth mentioning.
Very briefly so that we don't stray too far from the topic at hand, the majority of schools and colleges receive at least some government funding. Most people private property and business are not government funded so they can set whatever rules they like on their private property. It is quite different, IMHO, when a college or other institution gladly takes John Q. Taxpayer's money and then tells him to go hang when he doesn't like being stripped of his rights while using the facilities that he paid for. Your argument carries some weight if we're talking about schools that are 100% privately funded, but those are a very small minority.
Smith, and Wesson, and Me. -H. Callahan
Well waddaya know, one buwwet weft! -E. Fudd
All bad precedents begin as justifiable measures. -J. Caesar