By the end there was literally one CS server I trusted to be friendly and busy and not running "rpg-mod" or "zombie-mod" or a thousand other adjustments I didn't like, such as "no-awp", "price adjusted" etc.
Just finding a vanilla experience became difficult, doubly so if you wanted more than "dust/dust2 only".
Add in the fact that these servers could send your computer files (in theory just maps, sounds and decals, but difficult to secure of course), and you can see why companies shy away, not just to have greater control of the experience.