Have people actually said that? I hadn't noticed, but geez. It's just a slogan! I don't see why any park can't call themselves whatever they want.
Kennywood, up until a few years ago, if I remember correctly, still called itself "The Roller Coaster Capital of the World." They've since dropped it in favor of "America's Finest Traditional Amusement Park."
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How dare you vanquish the Steel Phantom without his consent? Fear the Phantom's Revenge.