Just as our parsha teaches us how important it is to avoid arguments and slander, it also teaches us the opposite side of the coin, the importance of differentiating between those who have sinned and those who haven't, between those who have sinned more and those less.
After God says to Moshe and Aharon
הִבָּדְלוּ מִתּוֹךְ הָעֵדָה הַזֹּאת וַאֲכַלֶּה אֹתָם כְּרָגַע:
Stand aside from this congregation, and I shall consume them in an instant".
Moshe and Aharon shout
וַיִּפְּלוּ עַל פְּנֵיהֶם וַיֹּאמְרוּ אֵל אֱלֹהֵי הָרוּחֹת לְכָל בָּשָׂר הָאִישׁ אֶחָד יֶחֱטָא וְעַל כָּל הָעֵדָה תִּקְצֹף:
"O God, the God of the spirits of all flesh, if one man sins, shall You be angry with the whole congregation"?
This is the first time Moshe uses the phrase “God of the spirits of all flesh”, he will repeat it later. Rashi explains Moshe’s words as a parable – "You are not like a human, he tells God, A human king, when some of his subjects have strayed, he doesn't know who they are and punishes all of them, but you know who has sinned"