Oznayim la'Torah: Because, having seen how the Kaparah on Yom Kipur is attained by the Par of Aharon, the body of which was burned outside the Camp, ¹ and the two Se'irim on the part of Yisrael, one of which was brought entirely outide the Camp, ² the other, the body of which died outside the Camp - we may have thought that this is the ideal way of brining Korbanos - half directly to Hashem and half to some other force (in His name). ³

Rashi (in Yoma, 60a): That the Z'rikas ha'Dam permits the bringing of the Emurim on the Mizbe'ach.