Maybe I did exaggerate a little bit, but seriously, Spaceballs as the worse? He might not like Spaceballs, but it is far from being the worse movie ever made, regardless of opinion. Just compare it to any farsical comedy made in the last decade, and it comes out a much better film. The Scary Movies? Disaster Movie? Date Movie? Meet the Spartans? Super Hero Movie? Epic Movie?
Plan 9 might score points for unintentional hilarity, but its obvious that it wasn't what the filmmakers intended, so its still terrible by all counts. Plus, there are others that are far worse:
Superman: The Quest for Peace
Hobgoblins
Cool World
Pumaman
Carnasaur
The Crawling Eye
Robot vs. The Aztec Mummy
Grinch Night
The recent remake of The Day the Earth Stood Still
Quest for Camelot
Southland Tales
High School Musical 1-312
Space Mutiny
A Sound of Thunder
The Neverending Story 3
Battlefield Earth
Wild Wild West
The Wild World of Batwoman
Electra
Alone in the Dark
Zoom
Manos: The Hand of Fate
Eegah
Zardoz
Gigli
Anaconda
Lost in Space (the movie with Joey from "Friends" in it)
Of all of these, Spaceballs is the worse?