State Parks vs Fed Parks.... that aside, this falls into the category "Trump, Elon and other wealthy folks do not use these services so they deem them "unnecessary"." When they want to go to the wilderness or some of the Trump family goes hunting, they have rich friends who they pay thousands of dollars for private access to the outdoors.
So govt funded and maintained parks are not a priority for them, and now they have MAGA agreeing that the US Park system is also unnecessary. The 325M people who access the parks each year likely disagree, and I'd bet some of the folks cheering for the firings now, will be complaining when they lose access to parks. They just don't realize it yet.