Most mass shootings are committed by adult men, that is true.
Census data shows that about 67 percent of adult men in the United States are non-Hispanic Whites.
James Alan Fox, a criminologist at Northeastern University, studied mass shooting data 1976 to 2019 and found that 64 percent of shooters were White.
So... 64%, 67%, some judgment calls obviously, since race is often not straightforward, but...
I think we can say my premise was FALSE. I was WRONG.
Why?
Fox also noted that media coverage tends to focus more on White shooters — possibly because most violence happens within racial and ethnic groups, not between them. So White shooters tend to have White victims — and to be covered more intensively by the mostly White media. And attacks that get more coverage are easier to remember.
That difference in coverage makes it easier for people (like me) to make false conclusions.