If the problem is not video games, it has to be something else that's definitely unrelated to guns. In this case, it is social media:

The shooting was not a result of any "one-on-one confrontation," Garcia said. It began after one partygoer fired a gun into the air "in an apparent celebration of music."
A second person "recklessly reacted to the gunfire and shoots into the crowd."
Most of the 19 injured suffered gunshot wounds. One person suffered a broken leg trying to flee from the gunfire, Garcia said.
"Any time you promote a birthday party on social media, you have no control over who to expect at your door," Garcia said. "Any time that you have to factor in the possibility of a bouncer and being searched at the door, you've already taken a turn for the worst."
Police are searching for two shooters.

You will not find in the whole report a single word about how it's dangerous and even crazy to bring a gun to a party. And yet, the problem at the heart of this situation is (and read these words again: "The shooting was not a result of any 'one-on-one confrontation' ...[but] a partygoer fired a gun into the air 'in an apparent celebration of music.'") that people brought guns to a party. According to gun ideology, two people are dead and 19 are injured because of Facebook.