There's a reasonable argument that Chrome OS is Linux--or at least more so than Android is. But it's not so much that it's "the wrong kind of Linux" according to purists as the article says but that it mostly addresses a different use case than installing Fedora or Ubuntu and therefore, IMO, it generally makes sense to treat them separately unless your point is that some form of Linux (and *nix generally) has a pretty large market share on both desktop and mobile.