In particular, a perfectly reasonable answer to the question "what am I going to find on this computer?" might be "Naked pictures of me/my spouse" if it's a non-work laptop.

It's extremely invasive for some random civil servant to execute an unexpected search on a device that most reasonable people assume is private.

As far as searching my work laptop, it was not harmful or offensive to me. It was strictly used for work purposes and there was truly nothing on the computer that they could do any harm with (to me or the company).

That said, under nearly any other context, I agree that it would be harmful and offensive.