iTunes was also unpopular with the Slashdot set because they had folder hierarchies for organising music and didn’t want something else in the way of their organisation.
As I recall it, my gripe with iTunes at the time wasn't that it would allow for metadata filtered playlists -- I thought this was great -- but that it would physically change the folder hierarchy of the underlying music libray to better fit its own data model.
I had my own music library organized as one album per folder, and only ~70-80% of it was properly tagged (which back in 2002, was actually pretty good for a collection of self ripped CDs going back 5 years or so). With no warning, iTunes decided to rearrange it into an artist/album hierarchy, which rendered the whole thing unusable with other software and HW players lacking sophisticated metadata support.
And you can imagine the havoc this wreaked among the part of library that was not tagged...
Now, this happened to me specifically with the first version of iTunes that Apple ported to Windows, back in ~2002, I believe; I'm pretty sure later versions fixed that. But that certainly gave me cold feet about ever wanting to try it again.