This is a good question and I think there are three answers:
- It would be too easy if all the options were right
- It encourages us to use other sources to translate the word
- They are computer generated options and therefore are not "checked" or "maintained" by humans.
If you believe another option should be accepted, please report it or send a message to the duolingo staff - and they will correct it (if it needs correcting).
Another odd scenario here is the it says "oops you missed a valid option" and it wanted me to check "leader" AND "lead" for "El dirigente". Since we are talking about occupations here, I'm not sure that I understand how "The lead" is an appropriate answer. Correct me if I'm missing something.
There are often inconsistencies between two exercises using the same word. "Manager" most definitely was in the Duolingo dictionary of "el dirigente" in a previous exercise. It seems one dictionary is not attached to a word throughout exercises; subsequently there are solutions that are marked incorrect. "El conde" is another word with differing dictionaries. We are Duolingo's beta testers.
I don't think that "lead" is the best English word here. (Then my knowledge of Spanish is negligible, so maybe I'm going out on a limb.) Lead is more like the first among equals rather than a step above like "leader" or "manager". Even "team lead" is usually one of the team that is in charge for a particular task but is not the boss.
This ("El dirigente") illustrates again why I so much dislike multiple choice questions where if you are wrong if you don't pick all the "correct" ones. Often one is more correct than another. Should you pick only the best or pick both? How far do you stretch it?