thats a fair question. i find it ironic that i like the mentor for the SAME reason you find it frustrating? it gives me a feeling of accomplishment when i find what they are looking for on my own. we might even remembr it better too? i mean, thers probally more than one good move to make when it's our turn (the alternates) but only one move leads us to what the lesson is trying to teach. the way i see it... the lesson wants to make a specific point... so we are kinda guided towards it? it doesn't look like we are penalyized for making those alternate choices... it jst asks us to find the variation that leads us to where they want us to go:) i'am a beginner and the Mentor is helping me lots. i like it. Good luck.
Frustration

It often happens that I'll be doing a chess mentor lesson, and I will be asked to make the best move. So I pick a move that I think is good, and I get the "That's an alternate winning line" message. Go back and pick something else. Why doesn't the message just say, "Although the move you've picked is just as good, we prefer Bc4 because of x, y, and z"?
It is telling you that, just with a different way of saying it.
It often happens that I'll be doing a chess mentor lesson, and I will be asked to make the best move. So I pick a move that I think is good, and I get the "That's an alternate winning line" message. Go back and pick something else. Why doesn't the message just say, "Although the move you've picked is just as good, we prefer Bc4 because of x, y, and z"?