Yes. It's their computer. We don't need to hand-hold grown adults, that's how we develop computer-illiteracy.

Nobody knows how to do anything because nobody lets them.

This is an interesting question. I started using computers in the late 90s when there were no guardrails and everything was permitted so I know what I am doing- or at the very least only blame myself if I fuck it up.

But your average 20 year old who only knows an iPhone would be out of his/her depth quickly.

Computers are no longer made for me.

To clarify, re-authentication prevents malware from doing what you said it would do. Regular people wouldn't need to use it.