I remember the first notable one was the tower at Texas University in 1966. Did we blame LBJ for that? No.
When a Bernie follower shot up the GOP baseball field two years ago, did we blame Bernie? NO!.
The fact is there will always be haters. Trump's rhetoric and rants over the border may be a symptom of this disease but it's not the cause of these shootings. Hell, even if one of these loons claimed to be doing it in support of the President, he still couldn't be blamed for the action of the shooter.
Let's put together a solid plan for better controls of WHO gets guns, not necessarily WHAT KIND of gun they have. There are simply too many of those types of guns to ever contemplate a buy back or confiscation.
Universal checks. NO felon gets any type of weapon. No cash and carry gun sales. These aren't intrusive of anyone's right to bear arms but they will help get control of some of the sickos.
If we blame Trump and the NRA, then we have to blame any President who has ever been in office during one of these shootings. We have to blame other hate mongers like the Black Panthers and individuals like Maxine Waters.