Consequently they have no inertia.!! They only can move by horizon pushing plasma tails like both Herbig Haro bowshocks do.
They have gravity by the eating of the local oscillating Axion-Higgs vacuum, which is the real gravity effect. Spacetime is changed by the eating and mass feels the gravity into the direction of the black hole..
Conclusion: Gravity is the result of pushing vacuum particles with less pushing gravitons produced by massive objects.
see: massless black holes in:
https://bigbang-entanglement.blogspot.com/2007/06/my-new-book-will-be-available-end-of.html
https://www.researchgate.net/publication/331230839_The_Electric_Universe_by_Electric_Dark_Matter_Big_Bang_Black_Holes_of_Quantum_FFF_Theory
https://www.researchgate.net/publication/324497489_Dark_Matter_Black_Hole_Galaxy_Hierarchy_according_to_Quantum_FFF_Theory#fullTextFileContent