Q1: Why is this described as a parody religion? Who determines whether or not a religion is a parody?
A1: Reliable sources. There is unanimity among reliable, third-party sources that the Flying Spaghetti Monster is a satire. Moreover, founder Bobby Henderson is implied to have said it was in an interview with
USA Today. "I don't know if (the FSM parody) makes a difference," Henderson says. "People who really need to get it aren't probably listening. But if anything, it might bring some awareness to undecided people out there."
In any case, Wikipedia's standard for inclusion is
verifiability,
not truth. The bottom line is that we report what reliable sources have said.