my understanding
I'm by no means an expert, but here's my understanding.....
Supposedly the pitching down moment is caused by the engines' location in the back of the airplane as opposed to wing mounted ones and where the thrust line is in relation to the body of mass being pushed.
As for getting the pusher, I believe that has to do with the smoothness of getting that nose up and maintaining that pull. If you pull it too hard you put some more loads on those wings or at least make the computer think that and get a pusher as means of protection.
Guys....? chime in.