For someone that cares so much about two-spacing I'd assume he'd also set up his HTML/CSS so that it actually preserves his two spaces after a period by some insertion of an HTML entity. As it stands now, if you View Source he definitely uses two spaces after a period but when outputted to the browser it's only one because the white-space is coalesced together by the rendering engine.
Except that he does. He only argues that two spaces doesn't look ugly in monospaced fonts but should be changed to smaller spacing when presenting variable fonts. No further explanation should be required as to why he doesn't go out of his way to break that.
He isn't trying to say "two spaces are superior", he is more saying "two spaces are more helpful for me, with my tools". Just because he prefers one form doesn't mean he hates the other.
