What is 'Alternative comedy'?

I noticed a comment stating "Not the nine O'clock news" to be "alternative comedy". This statement surprised me, since I rather consider it to be classic comedy, straight sketch-based comedy in the same lines as Benny Hill, Marty Feldman and many others. Don't get me wrong, I know the jokes are often daring, and I did enjoy it, but I don't find it at all as "alternative" as the Cambridge Circus gang. They were truly alternative, working on alternative concepts, eventually branching into two hit series, "Monty Python Flying Circus" and "The Goodies".

I have checked out some definitions of "alternative comedy" and the same thoughts come to mind: The series that fits the definition best is MP and The Goodies, both made before AC is supposed to surface.

MP is alternative in the way that they have no punchlines, the sketches flow into each other, which is confusing and funny, combined with bizarre animations.

The Goodies also got rid of the classic sketch-punchline model and made shows around themes, more or less stories, often highly surreal and sometimes with rather extreme slapstick.

Comparing that to NTNON, NTNON seems very mainstream indeed, rather similar to Marty Feldman's shows 10 years or so earlier. Funny and daring, yes, certainly influenced by MP and Goodies etc, but I fail to see on what way it is different. To me, NTNON is simply good british humor. Nothing wrong with that, I just want to question the term "alternative humor" here.