Tboneous, I think you have run face-first into an issue of "worship" as shorthand within a specific subgroup, namely white, suburban evangelicals, (though surely plenty of people in this subgroup are non-white, urban or rural, and outside of evangelicalism) particularily in America, the UK, and Australia.
We tend to draw from the same pool of artists, as named above (Chris Tomlin, Paul Baloche, Hillsong, etc) whose music receives airplay on Christian radio, who are featured at large conferences across the world, and whose music is backed by large Christian record labels. There are a lot of us who are descending onto music stores seeking guitars. amps, and effects that will help us to sound similar to the guitarists on those recordings.
Indeed worship music is any music that is used in religious gatherings or with the intent of bringing glory to God, but in the world of guitarists, a large number of us use the word "worship" as shorthand for the specific genre of music we've been discussing. So when you bring up other styles of music used in worship, we are not trying to pretend they don't exist or aren't valid; we just are speaking from inside of our realm of experience.