Q: is the gravitational field of a sphere at the center zero?
A: yes but no but yes but no but you are moving the goalpost!
And this is why. The concept field strength vs. net effective value is something you aren't grasping. Had you known anything about the subject prior to deciding to becomea Wikipedia-based expert on it, you probably would have gotten it.
Anywho, dear, you've just become boring at this point. I'm going to go make some soup and not waste anymore time on you. Toodles!