Is it considered normal, polite, or legal for pilots to use this airport as a base to repetitively and intentionally fly over my apartment 100 times a day?

This airport has 2 different flight schools based from it and over 100 private pilots own or rent hangars to store their planes. There are legal heights all planes and helicopters maintain when over residences but as long as the pilots meet these FAR rules they are both legal and polite. Perhaps you should rent an apartment not near an airport?

It is an airport and several businesses are run out of there. I would say yes