I don’t know the origins of FSM or whatever
FWIW, I never really cared one way or the other for FSM, but it was created as a rhetorical device, designed not to counter belief in God, but to counter the trend of people enforcing their religious beliefs on others through the law. i.e. “if you’re going to legislate that my kids have to learn religious creation myths in a public school’s science classroom as if they were fact, then please allow me to demonstrate what a bad idea that is using the FSM, since we cannot Constitutionally favor one religion over another”.
The trick is, there are plenty of real religions with alternate creation stories that most people would not want taught in a science classroom. I think that’s an area where the Satanists, for example, have done better work keeping the argument civil than the FSM people IMO. You don’t always have to jump straight to an extreme to get your point across.