I was always under the impression that Sonic was a B-list series over there. They don't exactly HATE him, but he's not the house hold name he seems to be in pretty much every other region of the world. IIRC it's because in Japan SEGA was more famous for it's arcade games than it's console games, and as a console centric series it just never took root in the cultural zeitgeist when SEGA was at it's peak. Despite what random /v/ annons will tell you Sonic has plenty of dedicated fans in Nipon, just not nearly as many as us.