That isn't that crazy, really. There are some bands that I generally don't like, but might like a song or two by. It happens.
What's funny is, even when growing up in the 80s, West End Girls, their first big hit, wasn't a song I was that wild about it. I mean, if it came on, I would usually listen to it, but there were tons of songs I liked more. I was very fond of What Have I Done to Deserve This, however. That was one of my favorite songs of 1987 at the time (which is saying a lot, considering how much music I loved from that year, and how important that summer was to me from several standpoints, including a musical one).
Even now, while I think West End Girls is a pretty cool song, I can think of a ton of PSB songs I now like more.