What were the people complaining about this time?
Rashi: They were complaining that everybody was allowed to enter (the Azarah of) the Ohel Mo'ed, but if someone went a fraction closer than his friends, he was Chayav Misah. 1
Rashbam: They were complaining that, bearing in mind that they were permitted to enter the Mishkan at will, 2 it was difficult to escape the urge to guard it or to assist the Levi'im in their Avodah, in which case they would day by day, they would slowly ut surely, die out. 3 3. Targum Yonasan: 'Some of us died by fire?, they were saying, ?some of us were swallowed-up by the earth and perished. It is as if we all perished!' 4
Rashbam: Since, at this time, the prohibitions in Vayikra 21:17 and 22:3 refer only to a Ba'al-Mum and serving be'Tum'ah.
To which Hashem responded by forbidding Zarim to come close at all, and by placing the onus of keeping them at bay on the Kohanim.
See Na'ar Yonasan, who elaborates.
