We find countless times, Chazal disclosing
the wrongs done by Bnei Yisroel and even
individuals like נדב ואביהוא or Noach where
there is a Machlokes if to be Doresh
Lignai or Lishvach. (צדיק -- בדרתיו)
In our case as well both the Yerushalmi and
Tanchuma have no problem disclosing
what the בנ"י said when they watched Moshe.
In the Tanchuma it is actually R.Yitzchok
Nafcha himself (who is the Doresh Lignai)
disclosing what the בנ"י said (Fat legs etc.)
We must assume that for some reason when it
is part of Limud Hatorah. Chazal held there is no
problem disclosing both the good and bad equally.
The point our Gemoro is trying to make is, when
may one sit down after the Nasi passes by
This we learn from the Man Deomar who is Doresh
Lishvach and they watched
for this reason Moshe walking into his tent.
Usually when the Gemoro quotes a Chazal to
prove a point The Gemoro quotes the complete
Chazal with all the details even if they are
not part of the proof.
In our case the Gemoro doesn't quote the complete
Chazal but tells you " כדאיתא (the way it says in
Rashi explains, the Gemoro omits this
part because it is דבר מגונה and not important
for our Limud.
Rashi on the other who explains the word "כדאיתא"
where does it say and what does it say.This is part
of Limud Hatorah to know what the Gemoro meant
with "כדאיתא" In this case of Limud it is perfectly O,K,
to disclose both the good and bad equally.