The problem is that with the stroke of a pen a law abiding citizen can become a criminal for doing something that was legal the day before. Then they use that to take away their rights.
Being that it is the job of an armed citizenry to check the power of an armed central government, it is a major conflict of interest to have that government be able to restrict who may own a gun and under what conditions. Maybe that is why the Constitution never granted them such powers... and in fact specifically prohibited it.
Similar threads
