LIGO detected gravitational waves from two black holes merged 1.3 billion years ago is impossible lie. 

A black hole can not be seen because strong gravity pulls all of the light into the middle of the black hole. -Wiki

Theoretical physics is not a monkey story, all theories must have a precise mechanism. What is the mechanism of gravity pulling light into a black hole? 

Gravity only attracts/pulls matter/mass, does light/photon/EM wave have mass? If not, then the black hole is impossible to exist. If yes, then gravity will accelerate incoming light and decelerate outgoing light, then light speed will not be constant, bigger starlight will be slower than small starlight.

Gravitational waves are disturbances in the curvature of spacetime, generated by accelerated masses, that propagate as waves outward from their source at the speed of light.-Wiki

What is spacetime? Matter or energy? Real stuff or imaginary? What is the curvature of spacetime?  What is accelerated mass? What exactly propagate as waves from accelerated mass at light speed? What is the precise mechanism? How to measure its speed? 

Gravity is coexisting with all matters/masses, constantly simultaneously pulling all matters, therefore, it has infinite speed. If the sun has a quake, all the stars and planets in the universe will simultaneously sense it.