Do people think improv is fake?

[Jared]

I was looking at that (ridiculous) channel 5 "iO vs. Zanies" thing, and several comments said things like, "They're just making the audience believe they made it up. Different occupation Different name different town......Same friggin' joke!!!!" or "Improv is a fraud. They practice the "games" and re-create them."

Then I remembered the episode of "That's My Bush" where an improv troupe shows up and a character says this to them: "No! We don't! [buttons his coat] In fact, improv comedy makes me sick! Because you act like it's totally improvisational when in FACT... it's formulas that you rehearse! Over and over and over again, and every night you pretend like you're making it up off the top of your head, and then you LAUGH onstage to make it look real!! I hate you!!! Do you hear me??!! [the players lean back in fright] I said, do you hear me, you sons of bitches??!! "

I found the transcript online but no clip of this speach.

So, I hadn't realized this is a widespread misconception. Where does it come from?

PS. let's not use this as a thread for debating the nbc5 thing or That's My Bush. Yawn.