(a) RASHI's short comment suggests that Rav Ilish is arguing with the Tana
Kama. He maintains that they would not sling the Korban over their shoulders
because that is the way Arab merchants carry their wares, and it is not
respectful to the Korban to carry it in that manner.
(b) RAV YAKOV EMDEN says that Rav Ilish is explaining that it is disgraceful
not for the Korban, but for the person who is carrying the Korban. Rav Ilish
is saying that *even though* it is disgraceful for us to carry something in
that manner, we still carry it like that to show our love for the Mitzvah,
and how we are willing to disgrace ourselves for the sake of the Mitzvah.
(c) The OR SAME'ACH (Hilchos Korban Pesach 1:6) points out that the Mishnah
in Parah tells us that water drawn for use as Mei Chatas can become Pasul
through Hesech ha'Da'as if a person diverts his attention from the water
from the time that it is drawn until the ashes of the Parah Adumah are added
to it. If a person carries the water in a pail hanging from a pole behind
him, the water is Pasul because his attention was removed from it, since it
was hanging behind him.
We know that Hesech ha'Da'as will also make a Korban and other Kodshim Pasul
(Pesachim 34a). Why, then, was it permitted to hang the Korban over their
shoulders, i.e. behind them?
The Or Same'ach suggests his own answers to this question, however, the
DEVAR SHMUEL cites an original answer. The Mishnah in Parah (7:5) says that
if one has to carry two pails of water for the Mei Chatas, and he carries
one pail in front of him, hanging from one end of a pole, and the other pail
behind him, hanging from the other end of the pole, there is no problem of
Hesech ha'Da'as, because it is not possible to carry two pails on one pole
in any other way. That is, since it is normal to put one pail in back when
carrying two pails, carrying the pails in that manner does not show
negligence and it is not considered a Hesech ha'Da'as. That is what Rav
Ilish is adding here. Since it is *normal* for merchants to carry a heavy
burden by slinging it over their shoulder, carrying it in such a manner is
not considered a Hesech ha'Da'as and will not disqualify the Korban.