Jazz and smooth jazz are very different things. People who like jazz very often dislike smooth jazz. (Frankly, I can't stand it, though I listen to jazz quite a bit; for example John Coltrane's "A Love Supreme" is one of my favorite recordings of all time.)
Or as Wikipedia puts it:
The term "Smooth jazz" seems to inspire controversy. Normal jazz purists contend that smooth jazz is, in actuality, not jazz of any kind, regarding it as a misleading marketing buzzword that represents an attempt to hijack the ostensible prestige of jazz in order to sell what is really a form of "elevator music". They consider the smooth jazz genre uninspired, lacking the depth of expression, harmonic and rhythmic sophistication, and complex improvisation that are hallmarks of traditional jazz; substituting, at times, trite and hackneyed musical phrasing.But there is no ID3 tag for smooth jazz. Id3 tags include one for Rock, and also distinguish many different kinds of rock (Southern Rock, Hard Rock, Progressive Rock, etc.). Many of those rock subgenres share fans much more readily than jazz and smooth jazz do.
This seems to me to be a significant oversight in the ID3 tag definition.
If any readers know who to lobby to change this, please let me know -- I think this could be a helpful change for music software.