Why has America become so violent with Obama running things?

So, either we have an inordinate amount of mass shootings/killings or we have a lot of false flags. If you believe the first one, you have to ask yourself why.

Why have Americans become so angry and violent during his regime? Does anyone recall a 5 year period where you hear about several mass shootings per year? I don't in my four and a half decades on the planet.

Is Obama installing this hostility in people? He was supposed to be a great unifier. He is anything but.