Somehow I've managed to interact with random homeless dudes my entire life without resorting to murder. He initiated contact and had the guy restrained, there's no need to speculate about a weapon.
5 years or so ago my coworker was on his way to work and witnessed a man doing a snatch and run. He chased him down and tackled him, restrained him until a bystander could assist, then waited for the police to arrive. Didn't involve choking the life out of the guy. It's not that difficult. If you are in a position to lock on a rear naked choke you have already assumed control of the situation.
If you can't resist putting them in a chokehold and holding it until they die, then yeah, don't get involved in the first place. But most people can avoid doing that.