Exactly, gravity is technically a theory. But like evolution, it's been tested so many times it's just regarded as a fact. Especially because people have seen it happen. We have seen animals evolve since the theory of evolution was introduced, and we have also seen gravity through space exploration and just walking around. It just so happens that the church is extremely slow at accepting ideas, it didn't accept that the earth went around the sun until the 1990's for example.
"gravity isn't technically a theory", sorry to bust your chops, it is a theory, reason why it is still a theory it is because we know too little about other aspects of theoretical physics to make any assumptions as to why things are as they are. There are few facts about gravity that we know and these facts are Newtonian principles, but overall we are still in cosmic darkness as to much of physics, we have theories and we are trying to figure things out, but it is quite complex set of problems that might take centuries if not millennia to solve.
You might know this conundrum under different name; quantum physics, string theory and theory of everything is what we are trying to solve.