I've been formulating a take on this sort of thing lately. Basically, I think you can broadly break music up into "folk" music and "art" music. I don't mean "folk" in the "acoustic guitars and banjos" way, more more in the "popular, simpler melodies originated and enjoyed by the popular culture" kind of way. The vast majority of rock music is "folk" music in this sense. "Art" music on the other hand is music that in many ways is aimed at sophisticated listeners. A whole lot of people don't like art music because it's not designed to for immediate gratification, it's more like a painting that takes more effort to understand, and might even require some knowlege of the artist and where his motivations lie, and might even require knowledge of painting to the point of being able to see where the artist changed things up. Vai, Satch, et all often straddle the middle ground between folk and art, or go straight to art. While Jazz started off as folk music, it has migrated nearly completly to Art. Mozart was not folk music of the day, and I'm sure many people didn't like to listen to him then either.
I don't "like" alot of BeBop Jazz, but I'm fully willing to admit thats because I don't know what I am listening for, and my ear is not developed enough to really hear the relationship of the harmony and the melody and what a given soloist is doing in that context. You arn't gonna hear me say that a particular BeBopper is "souless" just because I don't get what's happening. What the hell is "soul" anyway? If it's all about the lyrics, then I guess that any instrumental music is incapable of having soul. Part of the "soul" in a Vai or Satch tune is in reality the fact that they can flat out play stuff that is impossible for some other people, or that the create sounds and textures with the guitar that other people don't.
So, if you don't like something, then consider learning what you need in order to appreciate it. It will probably open you up as a musician. On the other hand, you may not give a shit about learning that, which is fine, but don't slag on musicians whose work you choose not to understand.
