Gravity cannot be explained in a simple sense as scientists only know it is there and not what actually causes it. Its a bit like your floating plate in that sense only it can be observed, measured, and calculated.
Gravity is taken into account when aerospace engineers design a plane, do you fly on a plane even knowing that it has been designed using, in your view, a flawed view of the earth?
Infact even your PC uses silicon which processes have been designed taking into account gravitational force, you probably shouldnt use a PC just incase.
Unfortunatly the FEM has no maths behind it and its principles are just a lot of nonsence and hear say from unscientific people who live in the dark ages.
If you look through the history of the FEM each time a major scientific breakthrough disproves the myth the myth gets changed to account for it.