Slightly related video, but TLDR people dislike Nickleback in particular because the band is a prime example of so-so musical talent and by-the-nunbers record companies conspiring to push generic music to popularity and stack fat stacks in the process. Plenty of bland bands exist for sure, though this is more a case of people going "I bet you this slop will make bank" and customers falling for it hook line sinker.
Not that I'm any better; I owned Silver Side Up back when it was contemporary and even today I still gladly sometimes listen to generic stuff (hell, see some of the stuff I post here). Personally as far as this sort of rock goes, while I unironcially like Photograph, I like Puddle of Mudd a bit more but even then mainly because of that one song in Ace Combat 5.