The primary reason for calling it an abomination is that if they actually plan on having this used (especially if by other people) it will spectacularly break the moment Chrome decides to make their quirks mode more strict.
It's a fun hack, although not exactly very unique. See also the very old by now "Website in a PNG file" concept, which does the exact same thing: https://gist.github.com/gasman/2560551
This will never break. I still think it's a bad idea, but not for that reason. Browser vendors are strongly against ever making backwards incompatible changes - especially a change like this that would likely affect thousands of websites. Chrome is not going to suddenly make their HTML rendering engine more strict.
It's a fun hack, although not exactly very unique. See also the very old by now "Website in a PNG file" concept, which does the exact same thing: https://gist.github.com/gasman/2560551