It's a bit of an odd list.

It mentions Imgur, but not which bits of Imgur are being filtered.

I'm not going to try to visit some of those sites but I have no idea if the entire site is filtered, or if very narrow parts are being filtered.

Cleanfeed has two filters. Thr first is IP/domain based and if the site is on the list then all the traffic will go through a proxy or deep packet inspection to check each URL accessed against the blocklist. Detecting/Sourcing the second level is much harder.