I take it you have just as much of an issue with the existence of Superman, Batman, Dark Knight, Skull Mountain, Harley Blackbeard's Lost Crazy Treasure Train, and Joker, and the former existence of Kingda Ka, Great American Scream Machine, Lightnin' Loops, Shockwave, Ultra Twister, and Sarajevo Bobsled as you do with Phantom Spire....right? Because all of those were clones (or near-clones) of already existing rides before they were built. Each of those rides was literally designed for another property then sometimes adapted to SFGAdv, sometimes plopped down exactly as it was.
Phantom Spire was proposed for another property in a survey. That's it.
If your offense at the ride is the fact that it's not a "custom, original design for SFGAdv," then you should be equally offended at almost the entire rest of the coaster lineup. Are you?