The basic concept of strong encryption is not something that most people understand. People are projecting their ideas of physical locks and warrants onto digital systems because that's what they understand. It's flawed, but it's hardly the first or even biggest/most important issue where poor understanding by the public leads to bad legislation.
Every now and then I have to drive through bumfuck Oregon, and the only radio stations are AM talk radio. It would be "educational" to spend some time listening to that every now and then. There are real people on the other sides of these issues that seem blindingly one sided to us. I think a lot of Congress probably just thinks that passing this kind of legislation (on encryption) will make most of their voters happy. Just like shutting down the EPA, or ...