"None of us is perfect."
Translation:Nessuno di noi è perfetto.
I am going to compare it with Spanish, my mother tongue; grammatically, both languages [all Romance languages, actually] have gender specific nouns, feminine-masculine, regardless of human sexual preference and/or orientation. The masculine is considered the GENERIC form of nouns and adjectives, that's all; it is pure grammar, nothing personal. As a woman, I do not take offense; actually, I even prefer the masculine because there's no doubt that NESSUNO of them [men] è perfetto! :)) Hope this helps to clarify your doubt as well as give you some relief. ;))
Not skilled in italian, and not an english major, but i'll take a stab.
This is the same as in English. Everyone is treated as a singular noun despite referring to multiple people. (E.g. "everyone is here." As opposed to "everyone are here.") "No one" works the same way. I honestly don't know if the english "none of us ARE perfect" is correct (although it aounds correct to us native speakers) or if "none of IS perfect" is likewise incorrect, but it seems from this example that, in italian, "no one" and "none of us" function the same where grammar is concerned.