@Cel: Sure, as with any acting, you are coming from a place that you know. Even so, it's obviously a set piece. I mean, does Momoko love beef jerky, yeah probably. Does the fact that she plays to the fans that she like shortcake really bother Chinami? Cause her stress even? One would hope not, that's their job to play to the fans' fantasies; Momoko's only doing what she's paid to do. Chinami's indignation's supposed to be funny, not a serious indictment of Momoko's character. But on the other hand, it serves the laudatory purpose of gently showing viewers that Momochi is a put-on, it's a shtick, and they're pulling back the curtains. I mean, we fans know this already having known her long before "Momochi" was born, but maybe some casual viewers have the mistaken impression that Momochi = Momoko. Momoko herself highlights this by specifically calling attention to the fact that her colleagues, who after all know her best, dispense entirely with the Momochi fiction. By letting the mask slip, they're effectively letting her have her cake and eat it too.
And as we have both wished for in the past, hopefully she'll be able to at least partially graduate from her one-note character and present a more well-rounded public face, like Sayumi has done.
The fact that Momoko had a ready prepared answer to Chisato's grievance was clue enough. But knowing it's fake takes nothing away from the hilarity of Chisato praising Mikitty, who couldn't give a flying rat's tush about giving advice to anyone, over Momoko.

Anyway, for the foregoing reasons I really like this clip.
@DD: Yes, the abuse-train is a fairly common setup on shows like this. It's a form of publicity. When celebrities get taken down a peg or two it humanizes them, showing that they suffer from the same plight as everyone else who has to swallow their pride and take criticism from their peers. It also gets people more interested in their personal lives. Does anybody really think that Brad and Angelina were on the verge of breaking up every 14 days for the past 8 years?
Regarding their faux outrage, I see it like this: If I greet my cute lil niece with an impish scowl and shout "C'mere ya little brat!!" even though there have been actual times that I thought she was being annoying, she knows that I'm not really thinking she's a brat right at that moment, I'm just pretending to be gruff for a moment, for comic effect. She wouldn't even think for a second that if I were really angry at her that I would greet her that way. I'd probably greet her coldly if I were. Similarly Momoko knows that if Chinami and Chisato had true grievances against her, they wouldn't be voicing them so effusively on a comedy show. They'd probably be reprimanded for doing so, even. It's obviously humor. Yes, you can single out instances of friction at some distant points in the past. OK, yeah I've had points of friction with my adorable little niece too, and probably with every single person I know, to boot.
I'm not trying to convince you or say that you're wrong, I'm just explaining why
I myself didn't think it was possible to take seriously. If you did, or do, that's okay, nobody's getting a grade or keeping score.