Sforno on Leviticus 10:6/ספורנו על ויקרא י׳:ו׳

1ראשיכם אל תפרעו, even though these dead belonged to the category of near relatives for whom even priests observe mourning rites, in this instance the law was applied in its entire severity seeing that these priests had been anointed with the holy oil of anointing. The Torah had spelled this out, writing כי שמם משחת ה' עליכם, “for you (pl) have been anointed with G’d’s holy oil.” (verse 7).

2כל בית ישראל יבכו, for two outstanding righteous people had been removed from them. They would therefore not be denied the eulogies due to the deceased (Sanhedrin 46)