Looks to me more like consistency in treatment. Why should a non-violent felon (examples below include drug possession many years ago, etc). be forbidden from owning a gun? And if forbidden from owning a gun, should they not also lose their other rights? Why only the right to self defense?
It seems pretty obvious that no one wants a convicted murderer to on a gun (or breathe, for that matter). But someone convicted of smoking something that was legal, then wasn't, and now depending on where you live, is again - why should they be prevented from owning a gun?