This is some kind of markup fail, I would imagine - and it definitely has occurred in earlier blog posts by this author but I chose to let it slide. How does one get this fixed, at least for future blog posts? @JCS ?
This can be a confusing area because I use multiple fora and they use overlapping and inconsistent markup languages, and then there are content creation systems that are beyond fora that use different markup languages again. (For example, in my time I have made a fair few edits in Wikipedia and its markup language is a whole world of additional complexity.)
For what it’s worth, you use double tilde before and after the text in the markup language used in this forum in order to get strikethrough but unfortunately that tells us nothing as we don’t know what software the author is using. strikethrough