if newton's gravitation could define the bending of light by gravity, the the general relativity wouldnt have come up. photos dont have mass and its clear from the fact that it travels at the speed of light. Gravity is an illusion that seems to attract things but in fact it bends spacetime; which is why a straight path seems curved. newton's law of gravitation is still used bcoz its simple and we seldom encounter such massive objects like the blackhole in practical life, for which it does not hold.

If Newton's gravitation could define the bending of light by gravity, then the general relativity wouldn't have come up. Photons don't have mass and it's clear from the fact that it travels at the speed of light. Gravity is an illusion that seems to attract things but in fact it bends spacetime; which is why a straight path seems curved. Newton's law of gravitation is still used because it's simple and we seldom encounter such massive objects like black holes in practical life, for which it does not hold.