I suppose they can charge anything they want, but I can also decide to NOT participate (and I do).
The first time we went to Alaska through Canada (2006) we were somewhat shocked to find they charged $20 a night for dry camping in their western Provincial Parks. This was very high at the time for dry camping with no facilities. The two parks we stayed in had polluted water and neither dump sites were working. The real kicker was when DW found a pamphlet describing Provincial Parks. In it they clearly stated that the purpose of these parks was to generate province revenue, not provide recreation, protect resources, or any other goal, just produce revenue. We have been to Alaska 5 times since, and have not been in another Provincial Park. Their choice, my choice.