As someone who isn't from the US it seems to me that you simply don't have faith in your government and that even the chance of a scenario where there could be an abuse of power is unacceptable even if such systems work outside the US. It comes down to the type of political system that only has two parties that creates such polarising opposition to one another. But that's another issue entirely.
Just because Americans are born with the right to own a gun doesn't mean they can own any weapon they like. There are already limits of what types of guns you can buy, so extending or retracting those limits shouldn't be out of the question if it has the potential to limit damage and death to members of society as a whole.
Essentially nothing has been done to address gun violence in the US other than encouraging the purchase of more guns as protection and that doesn't seem to be working.
RE: Reality Check: Trump Did Not Make It Easier for Severely Mentally Ill People To Buy Guns