Although I am a gun owner, I'm not in a position to comment on the US Supreme Court Ruling or the Second Amendment, since I am not a US citizen. I would like to share, though, the situation on gun ownership in the Philippines.
At present, private citizens are allowed to own only one handgun and one shotgun/.22 rifle. You must present documents like psychiatric and police clearances . . . in theory, at least.
That said, I can personally attest that despite this, it is fairly easy to acquire a firearm through legal channels (and even easier to get one illegally, especially assault rtifles).
My country is a living example of the cliche '"If you outlaw guns, only outlaws have guns." Every campaign/election period there is a nationwide ban on the carrying of firearms by private citizens. Yet this has not stopped political killings in the least.
Admittedly there are a few cases of legal gun owners commiting murder.
There is no perfect system. Even if the requirements were strictly adhered to, a few psychos would still fall through the cracks. So all I can do is make sure I am not one of the casualties.