Just experienced our first Non-refundable campground

It is funny how these contracts are seen as a one way street. Folks are indignant when a park has a clearly stated no-cancelation policy, and expect that the park should accommodate their change in plans. Yet the same folks would be apoplectic if the same park cancelled their reservation (say because someone else were willing to pay more for the same spot).

You knew the policy, the reason you are cancelling doesn't matter at all, it is not on the park to eat the cost of your change.