It's not necessarily bad, but "best" books should be judged on rating, not recognition. With this rating system a book with 1000 reviews rated at 3.5 stars would score higher than a book with 500 reviews rated at 4.5 stars.
I used to balk at anything on the "best-sellers' list," assuming the majority would be poorly-written beach read material, but I realized that there can be compelling reasons to read beyond the literary merit of a particular work. Pop literature can help us understand and analyze the culture we're living in, tap into the zeitgeist, participate proactively. It can lead to moments of cognitive dissonance, for sure, but that's healthy.