I take the values of reason and freedom as a given. I don't question those values, only recognize that they are implied in the skeptic's question. Morality derives as a consequence of those values. So if someone said they valued reason and X, then they must value X generally. Otherwise they'd run afoul of valuing reason.

What value we choose to impose on something is always subjective, it comes internally. There is no "value" within the material of a thing. There's only our imposition of value.