Vandalism or art?

Above are 3 examples of the many pieces of  “art” produced by just one person across 10 national parks right across the western United States. Unsurprisingly, the National Parks Service has issued a press release saying “Vandalism is a violation of the law and it also damages and sometimes destroys often irreplaceable treasures that belong to all Americans.”

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On the other hand, here are some of the temporary artworks the UK’s National Trust has willingly allowed, including in a National Park:

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Are both organisations right? Or just one of them? Would the US National Parks Service agree with the UK National Trust that if it’s temporary and for a good cause it’s OK and won’t invite damaging copycatting”? Or not?