The Pizzagate conspiracy was created to cover up any media coverage of the police reports from the early 90s when Trump was hanging with Epstein and dumping 'used' underage girls at a pizza parlor the next morning.
The Piazzagate conspiracy theory was created by bored 4channers to see how ridiculous a story they can invent and how many people will just believe it. I don't think anyone realised it would get as big as it did and then they did it again with Q.