Which begs the question of at which populatity point does a band's music turn from bad to good. A one point for instance Coldplay was just another band giging around the UK and had a single on a small indie label. When did their output magically become good? 1000, 5000, 10K fans? Enquiring minds want to know...
I think some of the 'popular' backlash arises when a band deliberately smooths out its sound in a clear attempt to sell more units. I still think Coldplay's first album is a great guitar album but subsequent albums centered all around Chris Martin's voice and piano, and I lost interest.
Similar with Metallica. Even when they were selling millions of copies of Master of Puppets and Justice for All, they still kept their core constituency, but when they slowed the songs down and made them much more user-friendly on the Black album, that's when people cried foul.
There's always the snob factor of not liking something after everyone else discovers them, but a lot of times it's the band's own fault.