This is a very perceptive question and I have not yet seen that any of the commentators ask it.

1) I would like to suggest that there is a difference between the discussion in our Gemara and the discussion earlier in the Masechta. In the first Mishnah on page 2a we learnt that all mincha offerings that were offered without the special intention for that offering are kosher with the exception of minchas chotei and minchas kanaus. The Gemara 4a said that we understand why minchas chotei is kosher because it is called a chatas by the Torah, and we know that a chatas without the special intention is not kosher. However why is minchas kanaus without special intention also not kosher? The Gemara answered this question by finding a way to compare minchas chotei and minchas kanaus. We do observe though from the Gemara that it is not obvious that mincahs chotei and minchas kanaus possess identical laws unless we can prove that they do.

2) However in our Gemara at the bottom of 10b it is different. We wish to know if it is obvious that for a minchas chotei, the kemitzah must not be performed with the left hand. The Gemara states that this is not in fact obvious, because Rabbi Shimon said that one should be careful not to make the minchas chotei beautiful, since it is offered by a sinner because he sinned. Just as the minchas chotei should not be beautiful, so also one may have good reason to believe that is possible to do kemitzah with the left hand, because since one does not require an honorable mincha, the left hand should be sufficient. The Gemara states that therefore we require the Gezera Shavah of "Yad" "Yad" to teach that the right hand must be used for kemitzah.

3) However with respect to not making it beautiful, the minchas chotei and minchas kanaus are exactly the same. The minchas kanaus is also offered by a sinner, and Rashi in Chumash Bamidbar 5:15 writes that this is the reason that one should not pour oil onto it; so that it should not be beautiful.

4) I therefore suggest that since minchas chotei and minchas kanaus are identical in the respect that they should not be beautiful, it follows that when the Gemara 10b mentions minchas chotei it is no longer necessary to mention minchas kanaus because the 2 are identical in this respect. This is not similar to the Gemara 4a where it was not obvious that the 2 are identical, and it was therefore necessary to mention both of them explicitly.

Wishing you a Kesivah vaChasimah Tovah and a Good New Year.

Dovid Bloom