Another counterpoint: When you start implementing all that dummy proofing, you make the software more and more tedious to work with for people who know what they're doing.

I think it's quite obviously an issue that needs balance. Some software is meant to be seamless to get started with, so that users can get something done once in a while, some software is meant to be used long-term by professionals and requires productivity. And yet, many people jump on anything they don't immediately understand as bad UX.