Translation:Women are strange.
It's more common for them to mean as you've written, but depending on context "여자들은" could mean either women or the women and the same for "여자들이".
Consider the sentence "The woman has a dog."
You could write "여자가 개가 있어요." and it's fine grammatically, since we're talking about one woman.
But most Koreans I know would use "여자는 개가 있어요.", since it's a little easier to see who/what the sentence is focusing on.
The tips in an earlier lesson taught us that 들 isn't used for generic statements, i.e. it would only be for "the women." If we are talking about women in general then we'd leave off the 들, so it would look the same if we were talking about women in general or one woman. Was that incorrect?