My understanding is that people don't want WoWMatrix to have it because not only does it bandwidth whore from other sites, it circumvents their potential to make money, not just Curse's via "Donate" buttons}. There was also a long-standing issue where WoWMatrix would grab mods from anywhere, not just where authors put them.

Either way, I don't use autoinstallers. I'd rather do it manually so I can run my own scans before installing crap.