It looked like you were saying that there are more left wing shooters than right wing shooters. I realize now that you're saying there are more left wing shooters than there used to be.
It seems to me that left wing violence tends to target the people on the right who promote violence while right wing violence tends to target innocent people whom the right has deemed unworthy of life.
If you want to reduce left wing violence, eliminate the right wing violence.
I'm less concerned about a rise in left wing violence than I am about the increasing reality that unless the left wing embrace violence, we'll all be killed.