Wow, I'm surprised this topic made it to this many posts. But I do have a few things to add.
If something is made badly, that is different then simply liking something. Anyone can like whatever they want, since entertainment itself is completely subjective. For example, the movie The Room by Tommy Wiseau can be your favorite movie of all time. However, it is a fact that it is a bad film. I like some bad movies and I admit it, but I'm not about to say "they're good". Now take this a step further with blockbusters. Here's where it gets trickier. When comparing, say, The Avengers to The Dark Knight, I just don't know enough about film to say which one is better. Still, I love both movies.
About the prog debate, I've thought a lot about it. You definitely need to be somewhat open minded to be able to appreciate polyrhythms, strange time signatures and more complicated song structures. The general mentality is that "if you need to work harder to get to it, or if something is harder to get the hang of, it must be better". For example, anyone can run a mile in 15 minutes, but 7 minutes is a bit harder to achieve, which obviously means you're better than the people who can't do it. Now, whether this applies to music or not is up for debate, but it is an interesting thought. I mean, anyone can listen to a catchy pop song, but put on something like death metal and the amount of people who are able to appreciate it is substantially less.
One of the main facts of life is that the brain grows and develops over time. When you're a kid, you're generally more immature than when you become an adult. You mature and broaden your horizons. Now, instead of thinking about life, think about music in this regard. Most of us start out liking a pop song, it's basic and easy to pick up. However, if you're interested in maturing and broadening your musical tastes, you branch out and find the genres that have more quality put into them. Again, you can like what you like, but with musical intelligence comes more musically intelligent tastes. Hey, some people are fine listening to catchy pop tunes and don't really care about music too much and that's ok. I still love watching Disney films, just like a kid, but a kid can't appreciate Citizen Kane, or Stephen King's The Stand (the book).