They think that only the police need to have guns, since only the police come into contact with violent criminals. Apparently the rest of us only become violent criminals in the presence of guns. The gun haters think crimes occur with plenty of forewarning, hence their dependence on that weapon of first resort, the cellular phone. The 911 operator said it'd take a little while for the cops to get here. This hardly rates a rebuttal, but I'll point out a simple fact.
Criminals generally go out of their way to avoid choosing a cop for a victim.
And given the benefits of resisting violence with the most viable tool for the job, the gun. Gun trigger locks are not likely to pass muster with anyone who actually knows anything about them. If not, the complexity of the device would have to be extraordinary. There's a fly in that ointment, though. Reliability and complexity tend to be antagonistic.