When you don't know who runs archive.is, you can also never know if he sold it to someone else (except if either party publically announces it).

I never said there are examples. However, "who you are" matters, even if you don't care. At least when the who is known, we can guage the trustworthiness and what bias exists, because there's always a bias. When who is not known, you don't know what bias to account for. That's not trustworthy and not reliable. And when the site is closed source and you have no idea how it's being run, nor by whom, you don't know "what you do" either.