So, it isn't SemVer that is a mistake. It's the author's opinion that software should always be fully backwards-compatible, which would then require all SemVer-using software to be version 1.x.x (or 0.x.x, if we're zero-indexing.)
Or, alternatively, if SemVer didn't exist, this post would probably skip it altogether and just complain about people breaking backwards compatibility anyway.
> To say it another way: If you need to make a breaking change to your API, it means you screwed up. Don’t screw up.
If you make mistakes, please don't make mistakes instead. News at 11.