Of course it is but the die hard gun advocates like Drump and his ilk will use it as a red herring to quiet any discussion of gun control. Add violent movies and computer games to the list of culprits. Never mind the only difference between countries with strict gun control and virtually no mass shootings also have same stuff.
When it comes to gun control, logic is thrown out the door by our fine political leaders.
Clearly the right to buy an assault rifle trumps "life, liberty and the pursuit of happiness". None of which those dead kids will ever experience.