Michael Moore grew up in Michigan, not far from Oxford, the site of the most recent school shootings. He writes in this post about what happened there, and he includes the full text of the fan letter that Ethan Crumbley sent to President Trump when he was elected. Reading it provides some insight into the climate in which Ethan was raised.
He begins:

In a nation born and built on violence, where there are now more guns in homes than there are people, a parent buys the son a gun as a gift. A Sig Sauer 9mm.

But the son is disturbed. Nonetheless, she takes him to the gun range. She wants him to be a good shot. She wants to spend time with him. She loves these mom-and-son days shooting guns. 

Then he wakes up one December morning, walks into his mother’s bedroom and blows her head off. He has four of her guns including the Sig Sauer 9mm she gave him as a gift. 

That did not happen this past week in Oxford, Michigan (about 19 miles as the crow flies from where I went to high school). It’s what took place on December 14, 2012, when the 20-year-old Adam Lanza took those guns his mother gave him to use when they went to the gun range together in Newtown, Connecticut — and after he killed her, he took them to Sandy Hook Elementary School, where he murdered 20 first-graders and 6 teachers and staff before he killed himself. The only gun he didn’t use in this bloody massacre was the Sig Sauer 9mm.

Open the link to read what Mrs. Crumbley wrote to Trump. She’s thrilled to have someone in the White House who supports her rights as a gun owner. But that’s not all.