This is a view I strongly agree with. While the “worked example effect,” which is apparently a key part of the platform, does seem to accelerate learning compared with discovery based learning [0], I do not think the learning achieved by the regurgitation of another person’s ratiocination is nearly as useful or rich as learning acquired by discovery. In my view, the best way to fully and completely understand something is to come to it in your own mind.
OK, as long as you're clear that this is an indictment of basically all ordinary undergraduate math instruction.
If you want to do this, there are at least two ways:
A) use the AoPS books, which present exercises before explanations, and expect students to attempt them first, or
B) Use Math Academy the way my son does: skip the explanation and worked example and immediately attempt the first problem. Only if stuck go back to the explanation and example.
(B) isn't what Math Academy recommended, presumably because you might be able to solve the problems in the current lesson, but still miss out on something else the lesson is supposed to teach you.