If you cut & paste your whole answer, it is better to be able to see if something else is wrong; but, assuming everything else was exactly like the answer, then "women" should have been accepted, & you should report it using the "report" flag on the previous page, where the question and answer were. If other mistakes are made, sometimes the computer "reads" what you put, and compensates for the erroneous word by finishing the sentence in a way that is confusing, because it tries to match the remaining words to what you start the sentence with.
No, Duo did not put the word "all"/todos in the sentence. It merely states the gender identity of a group. If there were some very young women and some older girl children where there might be some confusion, and someone needed to identify that all of the women were, for example, old enough to legally drink, perhaps someone might say about the group, "They are all women," but that is a more complex statement with more context, than Duo's simple sentence. Better not to add things that aren't there.
Normally, if you forget to type a letter when answering, it recognizes that you forgot a letter. I was perfect until the last question, this question, and I put "the are women" instead of "they are women" and it marked me wrong. Anyone else ever miss a letter and get the question wrong? It sucks!
Yes, if the Duo/computer sees that what you put matches a real word, it will usually define it as the other word, so you'll miss it. Duo cannot know whether you know the difference between "they" and "the," it only knows "the" does not match its data base of correct answers. Most everyone has probably done that; don't worry about the small things, but push on. When I hurry sometimes, I don't proofread the answer I give, and I should!
If you had a reason to differentiate between two groups of single and married women, I found a few new words. You could say Ellas son esposas (wives), y ellas son solteras (single women); also, a new word to me, Ellas son casadas mujeres. (They are married women, or Ellos son casados hombres, (They are married men.) Single men, my translator said, was soltados hombres. I don't know why the defining word is not AFTER the noun, like hombres soltados, o mujeres soltadas.
Perhaps a native speaker will clarify which word order is correct?
I found another translation that means "handcuffs," which made me laugh! ;-)
LindsayTra9, at least you would have been understood if you SPOKE it. :-) But when it is written the two words are homonyms, which mean they sound alike but mean different things. Many people say that they are learning a lot about THEIR (another homonym!) native language that they didn't pay much attention to in school! It's a benefit, like WinterSoldier said!