I see many other countries in LatAM, Asia etc having just as many beautiful places of nature. And then in Europe there’s the beauty of e.g Gothic architecture in cities that are kept (mostly) clean.
I do agree there's plenty of places in other countries that have natural beauty, but the US has a combination of very large natural spaces, kept in a mostly natural state (not over developed), and does a decent job maintaining it. This is relatively rare (although the US is not the only one).
The US Forest Service has nothing to do with the amount of ads and billboards in US cities.
Because it's important to put Americans in their place. They are not good, and must be reminded that others are better.
Anyway not hating, just giving some other examples.