R/S is meant to ultimately increase the value of the stock. It's meant to benefit the company which benefits the investor. Just because they can do this multiple times doesn't make it legal.
Instead of me spelling it out for you, let's have some fun. If we were to decide to sue, let's put a case together purely as an academic exercise. Anybody on the board can participate. In the end, right and wrong is decided in a court of law.