So when I accelerate at a constant rate in my car, I should run out of gas instantly?
No, but you'll run out eventually.
Any and every massive body, from the smallest particle to the largest galaxy, creates a gravitational field. Fields move radially outward with constant flux, which accounts for the proportionality to 1/r^2. The space around masses
is essentially "warped," as is directly observable by the bending of light passing through large gravitational fields (for example, starlight passing near the sun during a total eclipse is observably bent). Also note that this effect was
predicted before it was
observed.
Speaking purely about gravitational fields, I can't explain to you what it is in the inherent nature of mass that causes it to create a gravitational field. I can try to provide you with some rational reasoning about why gravity makes more sense than UA.
In the RE model, nature is not selective. Any laws that apply to one object apply to any other. Gravity affects me just as it affects you, baseballs, bullets, airplanes, the moon, the earth, the other planets, the sun, and galaxies. Gravitational fields (and hence, gravitational forces) occur in the presence of mass, and they have always been observed to be attractive.
In the FE model, UA applies to something under the earth, which holds us to the ground. If it applied to the surface of the earth, I should be able to throw a piece of dirt and never see it hit the ground. It must also somehow apply to the sun, moon, and stars, as they do not crash into the earth. This force does not apply to me, though, nor you, nor any creature on the planet. There is also seemingly nothing
causing the force; it just seems to happen by necessity.
I hope, taking nothing else into consideration, this is some clue as to why the FE theory seems illogical.