I don't think they get it..."Non-essential" covers a lot of pretty essential things. Custodians are non-essential. But without them the trash piles up pretty quickly.
Non-essential is a lot of things that make the Government work...
The people here that want to fire Government Employees have said for years that Government doesn't work. So they want to strip the Government of the ability to work so they can say they were right.
Here is the problem with their thinking... there are plenty of places in the world where Government not only works but cornerstone of their economies working as well...
Example: Education is one of the best return of Investment a country can make in society. The US is the only major country in the world which has privatised education to the levels. While the rest of the world educated their brightest students regardless of the economic background, they actually invest more money in disadvantaged areas and offer them the best courses (effectively free) if there grades are good enough. It means that kids from the poorest backgrounds or just middle class kids can go to the best courses in the best universities regardless of there economic background.
Those kids leave college with effectively no debt and education which is best suited to them. This is considered the least they can do for the next generation. It is what they received themselves and what they can give to the next generation.
The US has some how got in their heads that what they received for far less (or free) they will charge the next generation.