Is this puzzle legitimate?

I've been browsing through Puzzling SE's most downvoted questions, when I stumbled upon one of those "bad communication I will xkcd cut your arm off" questions. I've heard similar questions with the same premise. The premise goes something along the lines of this:

Two sons and two fathers were standing under the sun. There were only three shadows. Why?

Please spend no more than two seconds pondering such a bad question, with the bad answer of:

The two sons and two fathers consist of a man, his father, and his son. The man then counts as both a son and a father.

I question the legitimacy of this question, as I probably should. Can those people really count as "Two sons, AND, two fathers"? I guess the question can be worded as, "Given a set of two sons and a set of two fathers, how can their union have three elements?" Does this rewording make an ounce of sense? If so, the answer would be correct.

I thought about it for awhile. I figured that two people of the past can be considered as two sons, two fathers, two grandfathers, and two grandchildren by the logic of the premise. However, we can also say that "There are two sons in the kitchen. There are two fathers in the kitchen. There are two mathematicians in the kitchen. There are two Spaniards in the kitchen. Altogether there are two people in the kitchen." In that sense, it seems perfectly legitimate? How do we interpret "and"?

Tagged "lateral thinking", but I don't know what better tag there is.

• I think it would be better tagged as meta IMO. But i dont really have a problem with 1 person being classified in multiple sets. We all wear multiple hats so it doesnt make sense to classifiy someone as 1 thing. Although i dont think it makes a good premise for a question. Oct 2, 2016 at 1:18
• I believe this is a matter of opinion. All natural languages allow for ambiguities. The fact that the PSE community would lynch you and break your arm if you posted that puzzle doesn't make constructs that are possible in speech illegitimate. Oct 2, 2016 at 9:03
• I would also argue that "One of the sons stood in his father's shadow" fits the scenario. Aug 4, 2020 at 14:52
• Certainly, everyone is a son (or daughter) of someone. Therefore you only need two fathers to satisfy the condition. I think using 'and' like this is perfectly reasonable, although uncommon and unnatural. Aug 4, 2020 at 20:58