If you really want to do some damage you just rent a uhaul
Or do we ban those too? Even you could snap your fingers, these mentally unstable people are just going to find another way to do harm. Same thing with criminals. And now, the criminals know, innocent law abiding people have no effective way to defend themselves.
TBH my opinion on gun control is my only real "far right" opinion. But I am completely against any form of gun control other than mandatory training and mental health checks for any at risk individuals.