As usual, Jim makes a good point - you've dispelled a myth I've believed for some time, Jim!
But given the rarity of truly-level-cue shots, I continue to think swerve is the reason that naji and Roger (and maybe others?) believe hitting above center produces no squirt.
I notice in one of Roger's posts he says "...cue ball deflection is not something I have to deal with when I hit the cue ball with english ... above the horizontal axis" - which isn't exactly the same as saying there is no squirt - so maybe we actually don't disagree on the underlying dynamics.
I think i am very close to an agreement that swerve cancels squirt, the one thing in my mind, is it because you, Dr. Dave and others shoot with cue elevated and hitting cue somewhat downward produces more friction with cloth, than shooting with level paralleled cue? I know You or, and Dr. Dave said squirt does not depend on friction, but i still have my doubts.