Here’s the deal. Scientists have a very good understanding of how gravity works. So much so that we can accurately predict the motion of the celestial bodies and slingshot spacecraft past them to get a speed boost.
Space-time curves. This has evidence to back it up. Real evidence. This curvature is due to mass. This has evidence to support it, real evidence.
This is not to say that there aren’t hypothetical problems with general relativity, there are. But it’s the best we have came up with so far, and it’s scary accurate.
Now, some people say because GR has a few problems, they’d rather believe that the earth is accelerating upward at ~9.8m/s squared?
This, to me, is absolutely unacceptable if you’re actually searching for the truth. The tiny holes in GR pale in comparison to the gaping canyons that UA has. Even defending UA by saying it’s somehow equivalent to GR in that they’re both flawed is silly and shows bias, which is anathema to real science.