some people in this thread have already said it but with a lot of extra words so I'm going to try and sum it up quickly.
El Paso shooter: I have right-wing beliefs about hispanics and I am shooting up a mall because of it.
Dayton shooter: I like leftist politicians, also I'm going to shoot up some people.*
not all violence inherits the ideology of the perpetrator.
(that about sums it up, but ive got an extra paragraph of clarification here)
*as of writing, the Dayton shooter's motives are still under investigation.