I got a better answer just by reading a definition of manipulation:
to change by deceptive or unfair means so as to serve one's purpose
It is as much about the means as it is about the purpose. So if you are manipulating a kid so they behave in a way that will help him get throug life this is not manipulation. But if you manipulate them into something that only serves you... Yeah that is manipulation.
So in case of convincing someone in a debate it depends. If you goal is to win a debate by manipulation, so you can feel as a winner, that is manipulation. But if you want yo educate them this is not.
This is the worst. Because they do not know what happened. It might be that they are completely new person with the same memories and just think nothing changed. While it might be that original person just died. And they will continue to flip the switch always spawning new person that will not be aware one person just stopped existing.