You’re absolutely right. Simple ≠ bad.
However, and I think you’ll agree, complexity, simply for the sake of complexity = bad. One of my recent obsessions has been Arvo Pärt’s Spiegel im Spiegel — it is so incredibly simple, but it’s also one of the most elegant and stunning chamber works that I know of.
I think that perhaps instead of “simple,” I should have used some other term that would have better described the compositional meat of most mass consumption pop-music. Formulaic? Not thoughtful? Uninventive? (I don’t want to venture into the pejorative, as I would have been indicting my own tastes at some level!)