I totally agree with this. I used to be pretty picky about how the term HTML5 is applied to new products, snippets, etc., but I've realized that it refers to a very specific context. It's much more efficient and descriptive to associate something with all the modern technologies we're using on client-side by tagging it HTML5. If we call something "modern", it is doomed to be slightly ambiguous and always shifting -- people called some technologies modern back in the '50s; are they modern now?

Even though calling something HTML5 may not be semantically appropriate, it's a nice form of metonymy and it instantly orients the audience with the frame of mind the author intended.

edit: missed a word