The Cohanim are restricted over and above other Jews with regard to certain laws:
לֹא-יקרחה קָרְחָה בְּרֹאשָׁם, וּפְאַת זְקָנָם לֹא יְגַלֵּחוּ; וּבִבְשָׂרָם–לֹא יִשְׂרְטוּ, שָׂרָטֶת. קְדֹשִׁים יִהְיוּ – A razor may not pass over your head, nor may you remove your beard. Do not cut your skin. Be holy… (21:5-6)
The prohibition on men to remove all their hair is actually not specific to Cohanim, and pertains to all Jews. The Maharil Diskin explains why.
Jews are defined by their actions, not appearance. A Jew is recognised by their force of good deeds and quality of character. In popular culture however, we know all too well that in the age of “celebrity”, a makeover is somehow newsworthy. Appearances are deceptive; the same person is perceived differently by looking different, yet remaining the same.
But how is the principle that appearances aren’t all they seem, taught from the laws of a Cohen – who actually have a uniform they are required to wear?
Perhaps a distinction can be drawn. The uniform is not universal – that would truly be meaningless. The uniform is exclusive to Cohanim. An on-duty Cohen is serving God in the Beis HaMikdash – the clothing is for the office, not the individual.
The way you dress might not be appropriate for a monarch or head of state. They have to dress up out of respect for the office, not themselves – not a hair can be out of place. But as God’s people, as princes and princesses one and all, we have to dress for the office too. Not everyone has to have a suit and black hat; everyone is at a different place. But we have to respect who we are enough to dress with class and dignity.