You should have revolted as a society when you started committing a live steamed genocide. If no one cares about children being literally shredded to pieces with their taxes, why would they care that someone 20 minutes away is "getting deported".
They're not scared, they're amoral. People voted for this, you forget.
Trump is just stupid. Many countries that rely on tourism do this, they have free or near free entry for citizens and ~$20-100 entry for foreigners. This helps them generate a significant portion of their annual budget.
I haven't verified these numbers, but quick searching days that roughly 14–15 million foreign tourists visit U.S. national parks each year, accounting for about 4% of total park visits. If we charge $20 per person for international visitors, that's $280–300 million annually... that's... Peanuts for the US.
I wouldn't be opposed to it at all if the fees are only used to preserve and maintain the national parks, but you know this fucker just wants to funnel the money into deep pockets.