Over 99.9% of gun owners do so responsibly, without hurting anyone or breaking any laws. To tell 99.9% of people they're not allowed to do something becasue less than 0.1% of people abused their right to it, should be a very concerning idea to anyone who claims to live in a free society.
If it was a simple matter of availability, then other countries with just high and higher rates of gun ownership as the US would see the same violence problems. But, that isn't the case, those countries don't have the same problems as the US.
All bans do is make people feel better about "solving" a problem without committing real time, money, and effort to an actual solution. I don't want to see another gun ban because I'd rather see something happen that will actually reduce instances of gun violence.
A problem with gun violence isn't a problem with guns, it's a problem with violence. Treat the underlying issues of violence: poverty, unemployment, homelessness, drug addiction, and mental health, and the problem will be solved.