Torah Connection - Emor

This week we learn about the specific right and responsibilities accorded to the Kohanim (Priests).  They have no land-ownership in Israel, but are guaranteed a livelihood from the Temple offerings.  They are set on a pedestal, but are obliged to hold themselves up to a higher standard than the rest of the populace - there are restrictions on whom they may marry, as well as whose funerals they may attend.

There is a section near the beginning of the parsha, however, which is somewhat disturbing from a Special Needs perspective:

16 The Lord spoke further to Moses: 17 Speak to Aaron and say: No man of your offspring throughout the ages who has a defect shall be qualified to offer the food of his God. 18 No one at all who has a defect shall be qualified: no man who is blind, or lame, or has a limb too short or too long; 19 no man who has a broken leg or a broken arm; 20 or who is a hunchback, or a dwarf, or who has a growth in his eye, or who has a boil-scar, or scurvy, or crushed testes. 21 No man among the offspring of Aaron the priest who has a defect shall be qualified to offer the Lord's offering by fire; having a defect, he shall not be qualified to offer the food of his God. 22 He may eat of the food of his God, of the most holy as well as of the holy; 23 but he shall not enter behind the curtain or come near the altar, for he has a defect. He shall not profane these places sacred to Me, for I the Lord have sanctified them.

Why are people with disabilities excluded from the holiest task of the Temple service?  Yes, they are included in most aspects of Temple life, but why is their presence considered "profane"?

I searched and found a few sources that address this.  Here is what seemed to me the best formulation of rabbinical thought on this:

While the exclusion of disabled kohanim from offering korbanot is Biblical, the rabbinic parallel is the exclusion of disabled kohanim from doing birkat kohanim (the priestly blessing, also known as duchening). Here, though, there's an interesting exception which we might be able to apply to the Biblical case as well. As formulated in the Shulchan Arukh, the rule is that a kohen who has a glaring problem with his face or hands is not allowed to do birkat kohanim, because people will stare at him; however, if he is a local resident and everyone is used to him, he is allowed.<14>

The point is made that this is a concession to prejudice:  Since we live in a society where the disabled are viewed as "different", the difference would detract from their ability to effectively represent the people in the public sphere.  Hence their exclusion from the highly visible role of serving around the Holy of Holies, but not from other tasks, wherein they are equal to any other Kohanim.  

This is not really a satisfying explanation, but it was the best I could find.... However, then I noticed a glaring exclusion from the list of disabilities.  Where in other contexts blindness and deafness are mentioned together (c.f. last week's Parshat Kedoshim, where we are admonished "You shall not insult the deaf, or place a stumbling block before the blind."), here only the blind are mentioned.  Why are the deaf not excluded?

I could not find any sources which address, or even acknowledge this discrepancy.  I wonder if the issue is that the deaf would not be visibly different, while the blind would navigate their environment more tentatively, thus betraying their disability? Or perhaps a different explanation? 

Any ideas???