I was once told be my teacher when discussing the topic of gravity, "Perhaps we just need to align our understanding and focus of where the debate is here" which really helped me to grasp where I was going wrong.
Primarily, I think this is where the misunderstanding lies for many people as it certainly did for me. In general, Astrophysicists theories are in relation to how gravity operates and not that it does not exist.
Lets look at the following for a further explanation.
“Is gravity just a theory?
The presence of gravity is not theoretical and is very clearly observed. It's the explanation of how gravity operates (as opposed to the phenomenon itself) that is indeed a theory, and has changed from time to time in the wake of new evidence, as scientific theories do.
Gravity (from Latin gravitas, meaning 'weight'), or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light—are brought toward (or gravitate toward) one another. On Earth, gravity gives weight to physical objects, and the Moon's gravity causes the ocean tides. The gravitational attraction of the original gaseous matter present in the Universe caused it to begin coalescing and forming stars and caused the stars to group together into galaxies, so gravity is responsible for many of the large-scale structures in the Universe. Gravity has an infinite range, although its effects become increasingly weaker as objects get further away.”
To summarise: Gravity is the force that causes two particles to pull towards each. It can be explained in simple terms and witnessed but scientific explanation of how it works amount to the current theories. There is a distinct difference here and this is where some people either get confused, misunderstand or hold attachment to group/sect views which derails them from really comprehending.