I see your point. In our travels we have run across some pretty crappy state parks, Ohio is one example. But in our neck of the woods, ND, SD, WY, MD & MN they are quite good. In ND I’ve found county park infrastructure (rest facilities, camp grounds, etc) far superior to the Roosevelt Park in ND.
Also the staffing is people friendly in state facilities, where national parks they tend to be animal friendly, and some of the staff will not hesitate to tell people that animals were there first and the place belongs to them.
National Parks have completely reversed what T Roosevelt imagined. He wanted to preserve a bit of nature for people. The lefties changed that to preserving nature for animals, to hell with people.
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Risks aside, other than cleanliness, I don't see much reason for banning dogs on trails. Glacier might be an exception if there's a major history of attacks on dogs. But my impression is the bans aren't for the dogs safety, rather the fact that some owners won't clean up after or control the behavior of their dog.
National parks have been taken over by federal econonuts in the barky years. They are not gone. barky left too many problems behind for Trump to address in one term.
It is easy to get all the toys out and make a mess but much harder to clean up and put them back where they belong.
I have not been to a National Park proper in years but the national recreation area we went to last year was pretty run down and staffed by a gang of hairy armpit women rangers that were downright surly.