If you go back to wave theory (Maxwell style) then the fact that electromagnetic waves can attract (absorb) or repulse (emit) gives a hint. Black holes absorb (attract) photons but do not emit (repulse) them. Gravity only attracts. I assume you agree that the more the mass of the black hole, the stronger the photon attraction (i.e., you can measure the mass of a black hole). So, perhaps the gravity of a black hole does not affect the photon attraction. Just emission (repulsion) is stopped at the event horizon.

To me it has always been sad that attraction/repulsion is just a +1/-1 in the Standard Model. Some helical explanations of transverse waves in the electromagnetic medium would allow the attraction but not the emission. Light can't escape, but gravity "can" in the only way it can, by attraction. I never understood how "exchanging" a "virtual" (undetectable) particle can have a 'binding' version that attracts. They have momentum.

So perhaps its the medium that matters and Higgs is not exactly a God particle after all. Just another 'disturbance ' potential in transverse helical waves in the gravitational medium.

That's my worthless 2 cents.