These kinds of setups are designed for people from countries with a low cost of living. For example in India, ignoring the rural/urban divide, the average wage is somewhere between 0.40 to 0.60 USD per hour. In that scenario $12/hour is incredibly good.
Actually, most of the UX designers in the community are American, recent HCI grads who are looking to buff up their portfolio with side projects. Does their UX feedback appeal to you?
Most of the UX designers in the community are recent HCI grads who have less than 3 years of experience and are looking to buff up their portfolio with side projects. It's not meant for professional UX designers who are already earning a good salary.