I feel it's close to "Those who can, do", in nuance. (literally those who do, do). Like, you're either やる奴 or やらない奴.
sidenote: やる can be "do" in a lot of senses, and is also sometimes used as a translation for a versatile four-letter English verb starting "f". This fact has been responsible for some of the funniest Google translation errors I've ever seen.