The priest must not become unclean because of a dead body, however there are exceptions for immediate family members. The priest must remain pure by not marrying a woman that is profane. And finally anyone with a physical deformity, and a long list of those is given, shall not serve in the sanctuary. Leviticus is written for the priests and so once again these restrictions are for the priests that serve before God and do apply to everyone.

Leviticus 21

The LORD said to Moses “Speak to the priests, the sons of Aaron, and say to them ‘None of you shall become unclean for the dead.