I'm not aware of anyone popular naming this fallacy, so I'm naming it here. The noncomparative fallacy is when you point out something good or bad about an idea without comparing it to its alternative, when in fact the alternative has the same property just as much or more. The noncomparative fallacy says, "Your idea has X problem; let's not talk about the fact that mine does too".
Ugh... so his argument is, "using the death penalty on people we think are guilty means people we're wrong about will get the death penalty, therefore we should not use the death penalty". But if the actual problem is that people are being wrongly convicted, what happens if we do abolish the death penalty? It won't save those innocent people; it will just replace killing them with imprisoning them indefinitely. According to his own description, after all, the problem is with the conviction system, not the punishment system. Maybe using a continuous punishment is better because it gives us the chance to let them go after we find out we were wrong. It's something you could feasibly argue for, but given the other reasons not to use prison as a punishment and the fact that 4% really is not as high as he makes it sound, it's not a given.
"In anarchy, someone could just go buy a gun without a license or a background check and shoot you!" Yeah, well, in a country with gun restrictions, someone could do that with pepper spray or a knife, or get a gun illegally, or a cop could do it; and for the thousandth time, it'd be much safer for the murderers because their victims would be less likely to be armed.
"In anarchy, a defense firm could turn corrupt and use their power to oppress people!" You mean... like every government in history has? Like police can and do with their defenseless victims and no competition, since the only way to hold them accountable is through government-run courts?