>Asking "why should I be moral?” already presupposes (in the question itself) the values of freedom and reason, as well as reason’s priority over freedom.

What about a person who values only their own freedom, and has no inclination to stack their faculty of reason against that of anyone else?

>the questioner must recognize and value the freedom of others, having no justification to do otherwise.

What if it doesn't occur to them that any justification is necessary?

I propose an alternative reason for people to behave in a way that approximates local custom, even if they have no natural inclination to think of themselves as equal members of society, with the "two-way street" that implies:

It makes life easier by removing sources of hindrance.

If I don't go around beating people over the head, then I won't get arrested for doing that. Maybe I really want to do that, but I want to be free even more.