Americans have so far put up with inequality because they felt they could change their status. They didn't mind others being rich as long as they had a path to move up as well. The American Dream is all about social mobility in a sense - the idea that anyone can make it.
In science 'fact' can only mean 'confirmed to such a degree that it would be perverse to withhold provisional assent.' I suppose that apples might start to rise tomorrow but the possibility does not merit equal time in physics classrooms.
