You're not wrong, but the question then becomes "why did the US send an advanced military defence system that needs a hundred highly trained American operatives to work".

I'm guessing the reason is a combination of politics (lots of American politicians with ties to Israel) and practical reasons (validate that these systems still work against the enemies of the state without actually getting involved in a war directly, perform analysis for future improvements for defence on home soil, get people behind Israeli lines to extract intelligence that might not be shared willingly).

Are there people of voting age that are exempt from paying taxes? Because I'm pretty sure the federal government has a huge database of its citizens already through the IRS. People who became adults after the last tax season and people committing tax fraud would need to register manually once, but I don't think that's such a big risk.

How would an illiterate dude living in a cave register to vote?

I guess America just can't pull of what just about every European country does, but even then you don't need this recurring manual registration mess. Just register everyone who filed a tax form last year and you should get most of the voting age population already.