It is implied that a Big Man has the option to simply walk away from a Small Man, and that preying on the Weak as a matter of choice for personal gain is thus Evil. Note that is entirely different from the Big Man who applies his power to the betterment of his tribe/city/nation by stomping weaker foes.
Haley, because she is Good, does not have the option of walking away here.
It is an unanswerable question what a perfectly "fair" and level playing field would even look like. But, in this case, it does not matter. That kind of obligation can only exist as a two way street. Crystal has the physical advantage and has not offered to negotiate over giving that up, even after Haley implicitly opens up that topic; so Haley has a zero obligation to throw away what advantages she happens to possess.