Merlin negative G cutout too quick?

Naw naw. I understand why the engine cuts out under NEGATIVE g manoeuvers.

The thing is I don't understand why any slight push of the stick should lead to negative g

You only get negative g when the total acceleration acting upward exceeds gravitational acceleration in horizontal flight. I don't see why this should happen at any slightest forward move of stick even in horizontal flight ... but perhaps you can enlighten me.