I think there's a difference. Going to a National Park requires additional resources above just having a National Park. People to assist you, additional infrastructure like bathrooms and campsites, etc. So I think it makes sense you pay extra to actually use the park and tax payers are paying just enough to keep the park established.

However, what's the extra cost in distributing the journal article? Hosting fees? A simple website where the paper author uploads a PDF? It seems like those costs are pretty small