Agreed, this is the real takeaway for those who think it’s unsurprising: they simply haven’t understood why it is surprising.

Definitely!

My understanding of knot theory is limited to having watched a few YouTube videos and reading the first introductory chapters of a book. A neat topic, but not one I'm going to dig too deeply into.

If that is the case the counterexample is the sort of thing a stubborn cynical and amateur mathematician (and programmer) may have found.