I put readthedocs in the same category because they try to look like the original source of the documentation. They lift the content and style, lock stock and barrel, and then try to rank higher than the actual project's documentation pages.
I have in the past, unwittingly read out-of-date documentation because it looked exactly like the source site, and I didn't pay close attention to the URL.
If they were truly ethical, they would not try to impersonate the original sites. It fails one of the most basic tests for trademark infringement (which is, essentially: "might someone in a hurry mistake it for the real thing?").
