"brand confusion"? You seem to be conflating copyright law with trademark law. If I had a copy of "Steamboat Willie", it wouldn't matter if it was H.264 encoded or md5summed or stored in an AES locker, it's still a copyright violation because I don't have a license for the content.
I'm not, the filer of the DMCA is. How else could just a uri being on a page cause a DMCA takedown of a page? That's what happened...they filed a DMCA because the text "http://whatever" was on a github page. Which sounds a lot like meaning trademark, but saying copyright.
That's why I don't consider this underhanded. As you mention, it's not copyrighted in the first place. Obscuring it is just closing the loophole that's being exploited.
I'm not talking about obscuring long passages of copyrighted text. Just obscuring one plaintext url that's on a page with others.
The project maintainer wanted to take it down. He has gone on record saying that the url shouldn't have been there in the first place, regardless of the DMCA.
If you put an encrypted blob on each line instead of a plaintext url, the DMCA notice will contain "My copyrighted work appears at <link to github line number> which decrypts to <my url> when using <decryption method>." It's exactly the same as the original claim. If you feel they're not technically sophisticated enough to file a claim like this, I think we'll have to agree to disagree.
In practice that "when using" stuff doesn't work. The DMCA request is denied by most providers if they can't see "the text in question".
This is from experience. Scrapers that change one or two words in a long passage of text getting away with it because it doesn't match. Or very lightly cropping 1000's of original photos. I will cede that it depends on the provider. Google and many others do some rudimentary checking for sanity before allowing a DMCA request. They would never have passed this one, where just a short piece of text was claimed as infringing.
