I'm not sure if this is what's confusing you, but も (like は) is a discourse marker, not a grammatical subject marker. Your English sentence doesn't make sense because it's trying to make "no one" the grammatical subject of a sentence which contains another full sentence with its own subject, but the Japanese sentence doesn't have that strict grammatical limitation.
It's just like we can say「夏はやっぱり、冷たいビールが最高!」 in Japanese without this corresponding to "Summer is cold beer is the best!", or some similarly ungrammatical English utterance.
I'm also not quite sure why you think the range must be specified. I mean, we could say 何も問題はないよ to mean "there aren't any problems (with the situation at hand)" or "there's nothing problematic (about what's being discussed)" without it being interpreted as saying that literally no problems exist anywhere in the world, right?