I don't know where you got that quote, because CA now allows PEX, although not every local jurisdiction is on board.
I don't have any knowledge about the leaching thing.
You have to remember that in CA, every time a cell phone company tries to get a permit for a new antenna, wackos come out of the woodwork and claim that the radiation is dangerous. And many parts of CA still do not have flouridated water, due to opppostion from the same wackos. Faucets with PEX internal parts ....thank the CA prop 65. Welcome to LaLa land!