When you start cracking down on who has the "right" reasons for owning a gun, you hit an impossible assessment.
So, rather than determine who has the "right" reasons, just don't bother with it.
The people have the right to own guns.
This right is so that we can form a militia when necessary. (in case of invasion or governmental incursions).
Some people will have guns for this reason, some will have them because they like them, some will have them because of the feeling of power.
But they will all have the right own them.
Even someone who just likes guns MAY be able to help if we're invaded.
Someone who likes the feeling of power MAY be able to stand against a Fascist government.
The POTENTIAL is there.
BUT, when you remove the weapons, you also remove that potential.
Err on the side of the rights of the people.