As I work for the Provincial Parks Department in Sask I can see the validity of Parks Canadas position. They purpose of parks is not to protect the areas FOR use but to protect significant pieces of natural and cultural heritage FROM use and abuse.
The old axiom of "leave only footprints" is not valid in todays parks. If at all possible there should be no trace of people in truly protected areas. It is not valid either to bring up other unfriendly activities to justify your own. Skiing, camping, development while occuring today have a significant toll on the envirionment and YOUR natural heritage.
I am a geocacher and would like to combine caching and visits to beautiful areas however the two activities should not be dependant on each other. Sadly, National Parks comprise a miniscule percentage of land base in Canada that loss of caching in parks is of no consequence to our activity. If caching is the only reason that you visit our protected areas then Parks Canada is right in insisting that the activity have an educational component.
We do not have a right to parks for our activities, nature has an intrinsic right of it's own to exist undisturbed. It is our responsiblity as cachers to treat every piece of land we use (because we are users) as if it were the last best place on earth and that will ensure Geocaching will not be banned everywhere.