I don't think you understand what I'm saying. I suspect you get easily confused by the subject matter and thus frustrated without reason.
So you're saying that when a policeman has reasonable suspicion he can stop someone? Yes, I agree.
It depends on WHY there was an initial stop. If the policeman had reasonable suspicion to initiate a stop, then the person is detained already. Them running after that stop, is just a violation of the detaining which the officer could legally do. In that case, the person running isn't what is creating the suspicion, the suspicion is already in place.
If the policeman doesn't have reason to detain, then the person can run all they want and the policeman can't do anything about it. And that's the way it should be. So approaching someone, having no other reason, and then the person runs, that is not enough.