Discussing the bad argument that you should believe that determinism is false, because if determinism is true, you can't determine whether or not you believe in determinism. So you should assume it is false, since only in that case can you do yourself any benefit or any harm.
Among other things I note that people are convinced by the bad argument for the same reason they are convinced to smoke in the Smoking Lesion.
Another possible rebuttal, even retaining the analytical meaning of the word choose, is to complete the demonstration appealing to the "if I can" in point 5 with:
6a - since you cannot choose free will, then it doesn't exist.
So, for the argument to be complete, a believer would have to add:
6b - I choose to believe in free will.
But then you have to show that you actually chose conclusion 6b instead of simply having reached it, which I don't think can be done.
Although I upvoted the article for your analysis, I don't feel that the counter-argument based on goodness is the strongest one can make.
Imagine that it is indeed good to believe in the correct metaphysical setup: still, you cannot derive that you should practically believe in libertarian free will, unless you have a way to distinguish from the inside how it feels to have libertarian free will from having deterministic free will, something that is probably impossible, or that even when you have deterministic free will is better to believe that you have libertarian free will.