The High Priest (Kohen Gadol) is not permitted to contaminate himself to anyone, including his closest relatives because he is “exalted above his brethren-upon whose head the anointed oil has been poured...” He is not permitted to compromise his holy status even for his closest relatives.
Sforno explains that the Kohen must maintain an elevated status in the eyes of the people. If he were to attend every funeral and contaminate himself with everyone’s deceased, he will no longer be revered by the people and seen as special. Consequently, his ability to be the disseminator of Torah and to be effective in his role as the Kohen will be severely undermined. He must maintain an esteemed and removed status in order to be effective. Thus, the Jewish people would be attentive to his teachings. (based on Gittin 52b)
Sforno does not translate the word בעל as husband as most do. Rather he translate בעל as master or chief, namely a leader among the peopleבעמיו . Thus, the Torah is providing a reason why the Kohen is prohibited from defiling himself with involvement with a corpse. Only if it is on behalf a close relative does others consider the Kohen’s involvement as an extension of his own honor.
