To be fair, there's a point in saying that Acid Jazz isn't 'true and honest' jazz, due to most of it just being funk, soul, or even hip-hop with jazz influences. Sampling Miles doesn't make you a jazz artist, and that's most certainly not dissing any Acid Jazz, it's just that a lot of groups that were previously described as Acid-Jazz just... Don't do much jazz in their work.
Smooth Jazz has more to do with Kenny G making one big fuckup, and the genre of smooth jazz becoming the arguable face of modern jazz while the focus of Smooth Jazz is on being music you don't have to focus on. That's pretty damn degrading, and usually Jazz is the most accepting of weirdo spinoff genres. There was a bit of an uproar when the PBS documentary 'Jazz' focused mostly on the Dixieland style of jazz, and furthermore mostly on Duke Ellington and Louis Armstrong, while treating such apparent sins as modal jazz, avant-garde jazz, and Miles Davis' solo work as a dark period.
Well it's kind of a similar thing with Nu Metal and Metalcore and metal elitists getting all pissed off and screaming at their computer screens. They'll say stuff like "Nu Metal is not metal cause it doesn't have any solos" or "Metalcore is not metal cause it's emo" or shit like that. The problem is, while that statements may be true for some bands, they're not for others. And they produce an unfair generalization.