I don't think they wrote the comment because of the impact to Valve. After all, they said legal rather than ethical and the page already seems to be gone (hopefully just a temporary hosting thing due to popularity rather than a takedown thing, but it will soon become the latter regardless).

If you want these kinds of things to stay up long enough for many people to see/use them you have to work around the legal limitations (regardless of whether they make ethical sense). Most commonly, make the site apply as a diff to the original content/assets the user provides.