That is just the mathematical description of gravity according to general relativity. We don't have a theory for how the uneven curvature of space happens and we don't have a quantum mechanical theory for gravity either (gravitons are hypothetical, not proven).

You are right, but my point is that general relativity gives us enough of a causal model for gravity that throwing up our hands and saying "It's a mystery" is unacceptable.

We could split hairs all day, but a more detailed mathematical model like relativity is still just a model. We don't know with certainty why it works, what the underlying mechanism is. I would rather say it's unacceptable to tell people what questions they can't ask than to criticize a particular model.

It is not unacceptable to say we don't know with certainty -- it's faithful to science. You are correct we have a mathematical "casual" model, but that model is entirely observational. We know what happens with certainty in virtually any gravitational situation, but we remain very uncertain about the underlying mechanism of action. It is faithful and mature to recognize this.