The mod community for Saints Row has existed for years, but it's never had any of the assistance that say Half-Life 2 modders receive. Mike 'IdolNinja' Watson, developer of the Gentlemen of the Row and Gentlemen of Steelport, said that for 2 years mods' emails were ignored. They didn't try to stop the modders, but they weren't going to help them either.
Evidently THQ told Volition, the developers of Saints Row, to basically ignore the mod community. Still, fans wanted to create their own mods, and were stifled by THQ. You can beat a man to death with a giant purple dildo, and that's not a mod. The Saints Row franchise is known for its emphasis on customization and wackiness.
Still, up until recently, the Saints Row franchise was lacking a supported mod community.