Pop music and it's appreciators automatically (possibly subconciously) deserve less respect because it's so easy. You don't have to do much, for example you don't have to discover it on your own, you're not required to make an effort to learn about music and it probably doesn't have to grow on you much before it sticks. It's handed to you and all you have to do is accept it. I think this is why people who are genuinely interested in music think less of it and that the actual quality of pop is less important.
To those who say pop is safe and does nothing new, I don't fully agree. Granted, some of pop does that, example Michael Bublè (my impression). Still, I think the most popular hits, like those of Lady Gaga these days or Britney Spears' "Toxic", have just about the right blend of old familiarity with a good dose of freshness. It gives people enough of the same old while piquing their interest with something new. I think if you buy the album and start listening to the songs which are not hit singles, that's probably where it starts to get really unimaginative.
I think many pop songwriters are very good at doing what they do and do find that right blend of familiar and fresh. It's probably not an easy thing to do either. Still, I can't quite find it in me to spend time on these hits ..
Mark Knopfler's latest was probably less imaginative than Lady Gaga's debut, but I'll get Knopfler's album.