He's playing to his base, just as the GOP Senators and Representatives are playing to their base in their pronouncements and actions. In the same radio interview where the question was asked about whether Farook's contact with a suspected (known?) radical should have raised a flag with the FBI, it was asked whether any kind of meaningful action by the government is possible given (1) that the nation is so polarized politically and (2) we're heading into an election in year. The conclusion was that we'll just get more of the same.''
The problem with trying to make it a gun control issue is that Farook bought his weapons some years ago, and by all accounts had not yet been radicalized at that time.