They make nothing. They're compensated for destroying things, and considering it's musk, they're likely given relatively little money in return for their time.
Even if the only thing you do all day is sit on the toilet and yell at the Internet, you're already a bigger net positive on society.
The reason he recruited a bunch of incompetent college kids is because nobody with any experience or wisdom would touch this rolling crime wave with a 10 foot pole
They're dumb kids. They probably see Musk as some kind of god. He gave them some line like "Hey, you guys wanna save the United States?" and they jumped at the chance.