A classic anti-technology strawman. It is like saying "Computers only use numbers, you can't do graphics or text with them".
At the very lowest level computers are entirely logical, but you can program one to deal with uncertainties and probabilities.
In fact that argument isn't quite relevant, unless you are arguing against the computers making the policy decisions, which I think was never under consideration.
Computers/technology can certainly be a strong tool to assist gun control.
One idea completely off the top of my head would be to data-mine as much info as possible about past shooting/shooters and then use this to help guide granting (or not) of gun licenses. With Bayesian this-and-that, the computer could give a number "estimated 0.000001% chance of serial killing" and refer the application to the appropriate person (e.g. a detailed analysis for people "at risk" (large probability), or a quicker check for "safer" people).