Exactly so.
So I am challenging the premise that "In reality, gun control is what sealed their doom."
To say "it sealed their doom" is overstating it. No one has made such an absolute their argument. But the fact is that gun control is responsible for no one, in that specific building, legally possessing a weapon on their body. (or in a book bag, backpack, etc.) That is a fact.
The "sealed their doom" quote is from the article in this thread which I was responding to. So, yes, someone was making that absolute statement and that is why I responded.