Δαφνη Ευτυχια Αρθουρος

There's an unspoken piece to it. "Boys will be boys [so therefore their boyish behavior cannot be and should not be corrected or punished]". And a connotation/frequent context as well: for example, "boys will be boys" is what I was told when I was sixteen and I complained about a classmate groping me. It was their excuse for not telling him "don't grope your classmates." It's frequently deployed in such contexts for such a reason.