Have any statistics to back that up? As of 2009, the total number of murders committed in the US by licensed concealed carry personnel are practically negligible.
You realize that in America, we don't just go around street corners handing Glocks out to people. You have to meet some pretty tight requirements just to purchase a firearm; and even more to get a concealed carry license. These are not the people who are committing crimes. Crimes are committed by criminals and they will find a way to get a gun no matter what the laws are.