Thank you, Captain Obvious. From the WaPo article:
"Last year, economist Richard Florida dove deep into the correlations between gun deaths and other kinds of social indicators. Some of what he found was, perhaps, unexpected: Higher populations, more stress, more immigrants, and more mental illness were not correlated with more deaths from gun violence. But one thing he found was, perhaps, perfectly predictable: States with tighter gun control laws appear to have fewer gun-related deaths. The disclaimer here is that correlation is not causation. "
So the other things that are claimed as "the root cause" here aren't even correlated...yet somehow the one thing that does correlate closely...