Why choose between "gun violence" and "Islamic terrorism"?
Those are trees, but the forest is at their intersection: It's looking like those two were freelancers, a lone wolf couple, who had no need to rely on support from "ISIS HQ" because they could pick up everything you need for a terrorist attack right here. America is the easiest place in the world to roll your own campaign of terror, off the shelf and perfectly legally.
When the NRA wins, the terrorists win too.