“If someone gets into your house they could take your house key, go to the Hardware Store, get a copy made and viola! Unfettered access to your home anytime they want!”
Does that not induce a panic attack? Good! Now how’s about:
“If you give someone your computer they could use Google Chrome to look up all your passwords, take them, and log into your accounts anytime they want.”
Actually, I hope your reactions were equivalent cause the two cases are talking about pretty much the same thing. Let someone into your home, give them your computer, you are trusting that person to not do anything malicious with that access. If that trust is broken it is not, I’m sorry to say, really a security problem.
I’d link to the article that inspired this but I don’t want to give it any more hits.