Patur Aval Assur,
First he asserts that there is always a benefit (even if unknown) which seems to agree with me,
Yes, though you seem bent on reframing my broader definition of benefit to personal benefit.
but then he says that you need a reason to go against your purpose. However, I never suggested that you SHOULD go against your purpose;
Ok, so why would you go against your purpose? 🙂
only that there is nothing forcing you to follow it,
Correct. That is the definition of free will.
and therefore if for whatever reason you want to do something that is against your purpose, there should be no problem.
How does that follow?