You clearly want to talk about something that is not resisting a push. This thread is not about that. That's why I "blew off your post", in an attempt not to "chase my tail". But I did it again just for you. Feel better now?
Well, like I said in the part 2 thread, you have to understand that you aren't actively resisting or pushing back in any way. That is to say, the resistance that the pusher feels at the most simple version of doing this exercise, is not the result of any additional muscular effort.
That is something that is strangely very very hard to do, as the natural reaction most people have when countering an incoming force is to push back against it or try and push back on an angle of some kind from the point of contact. It takes a while to unlearn this response in a static position, and even longer in a dynamic one.
This is why Mike Sigman wrote in one of his blogs, that most people he has met push back from somewhere else, even if it isn't from the point of contact and think this is "internal". I'm certainly guilty of that in the past.