The Top 10 Mass Gun Shootings in the United States

[MadZealot]

1) Just because it's specific doesn't mean it isn't arbitrary. You can specifically prohibit lots of thing without any sound evidence or logical motive to do so.

Barring people who can't stand trial, or take care of themselves, or are found to be dangerous, from owning guns, doesn't sound arbitrary.  It sounds rather... sane.

2)People who are legally "Mentally defective" is NOT the same thing as everyone who has a mental illness.

Nobody said they were the same; in fact I have given you specific info showing they're not, as far as concerns this law.

There are plenty of mentally ill people who are not "individuals found unfit to stand trial, incompetent to take care of their own affairs, or a danger to themselves or others." So the current law is not, in-fact, the same as what Castus is describing. If the law followed Castus' recommendation, there would be many, many more people on that list, including many people with manageable and non-dangerous illnesses.

I went back and read what he said. What he says does not align with or describe current law. 
And yes, there are plenty of mentally ill people who are not "individuals found unfit to stand trial, incompetent to take care of their own affairs, or a danger to themselves or others." If an individual doesn't fall into those prohibited categories, then the law doesn't apply to them.

As an aside, I think the fact that anyone who has been in a mental hospital is barred is outrageous. There are lots of people who voluntarily go to such institutions, and they should not have to surrender their constitutional right to bear arms. My own grandmother was in such an institution for a while, and she did not have any conditions that would make her more dangerous than anyone else.

 
I haven't looked too much at the nuances here, but the laws on this vary by states. Some only temporarily bar gun ownership after involuntary commitment.  I'd expect the reason for commitment is taken into consideration.
And I don't know if voluntary commitment is a disqualifier anywhere.  If you're aware enough to seek help, then I suppose you're mentally fit.  In my own experience, I checked myself in for a massive "depressive episode" at the end of 2012, but I've bought a few guns since then.

[MeadowRae]

No slight to your schoolmate. The worst mass shooting in US history was committed by the United States Government. 

(Link code fix - Sunflower)

Not to detract from the conversation, but the West Virginia Coal Wars aren't even mentioned in WV History class, and it was "the greatest insurrection since the Civil War." All they wanted was fair pay, and the government stepped in. https://en.wikipedia.org/wiki/West_Virginia_coal_wars

[Hariti]

Not to detract from the conversation, but the West Virginia Coal Wars aren't even mentioned in WV History class, and it was "the greatest insurrection since the Civil War." All they wanted was fair pay, and the government stepped in. https://en.wikipedia.org/wiki/West_Virginia_coal_wars

They are talked about in upper-division Appalachian history classes at EKU, but that's the only time I've heard them mentioned anywhere. Stuff was intense; there were tanks, bombers, Thomson guns, and even British Lewis Guns brought in to put down the mine workers.