I've been listening to a lot of commentary in the past couple of weeks related to the San Bernadino shootings and in none of those conversations have we been reminded of the Planned Parenthood killings, nor of the church shooting by the KKK adherent (the Charleston Church Massacre), or the familial shootings like the one in Troup Georgia that killed 5 people. If you look at the 353 shootings this year tracked by http://www.shootingtracker.com/wiki/Mass_Shootings_in_2015 you'll see only one that was related to Islamic terrorism. Couple that with the data that gun deaths are in decline (suicides are inching up) since the 90's and you have to wonder at the hysteria being created by Trump and the media. (http://www.pewresearch.org/fact-tank/2015/10/21/gun-homicides-steady-after-decline-in-90s-suicide-rate-edges-up/)
The Washington Post as an analysis at https://www.washingtonpost.com/news/the-fix/wp/2015/12/10/to-many-christian-terrorists-arent-true-christians-but-muslim-terrorists-are-true-muslims/ suggesting that Christian shooters are "excused" from the terorist label simply because Christianity is more familiar than Islam.
N.B. These numbers do not include the over 900 police shootings that resulted in death so far in 2015.