I tagged this question as homework, and the user replied that it wasn't homework, but a practice problem for exam review. In my view, exactly the same question could be asked as homework and exam review, and the purpose of the questions is exactly the same (i.e. teaching). Hence, I think the homework tag should pull double-duty here. Do you agree?
Yes (I agree) ;-P
The reason why is pretty much what you put in your comment on the linked question:
My opinion is that the "homework" tag is there to say to answerers "don't just give away the answer because then the questioner won't have to reason it through." For final exam review questions or homework questions, the goal is to give hints towards the answer and have you work towards the rest of it as much as possible.
Basically, I would say that
[homework] applies to any question in which we shouldn't give a full explanation in the interest of letting the OP get full educational value out of the question.
(However, I don't think this applies to the specific question you identified, for reasons explained in my comment on that question.)
No. The homework tag should not exist in the first place. We shouldn't categorize questions that need partial "hint" answers because such questions are antithetical to the Stack Exchange format.
If a question elicits the thought "I shouldn't give a straight answer because I'd be giving too much away", then the question is off-topic to begin with. Any homework-like (or exercises-like or whatever the hell we should be calling this [a]) questions should show effort and focus on a particular conceptual or technical issue that has the OP stumped.
I beg all reading this to comment on homework-like questions helping the OP pose more focused and well-posed questions whenever you can spare the few seconds it takes to do so.
[a]: Please read this meta post regarding re-naming the homework policy.