I'd say this explanation still seems to be too complicated: at least from the eyes of a one-boxer.

That which determines the choice of either option may as well be a non-intelligent flip of a coin, the mechanics of which are just as deterministic as the computations of the contestant's brain. It doesn't matter by which means the decision is made, all that matters, for the one-box strategy to hold water, is that the predicted decision = the actual decision: only an affront to determinism (which is arguably in principle impossible) could alter this. It does not affect the result that there is no direct, time-goes-forward causality.