Hey there, OP here.
These are good questions, though I disagree with the characterization here. Like: I don't think anybody's circumventing the DMCA, so much as tacking on additional measures not required by law. Anybody who's doing algorithmic enforcement, including YouTube and newly Vimeo, is in the same boat; in large part it's the result of negotiations with media partners who demand it in exchange for access to content. So, they're doing something separate from what the law requires (in addition to what the law requires) in order to satisfy partners... not really circumvention.
BUT it sucks. And it especially sucks when it's done in a way that doesn't respect users. And I've written about that lots, though not so much in this particular piece.
Sites have all kinds of "guidelines", and some of them are offensive and others aren't as much. Vimeo used to prohibit video gameplay uploads, for example; that's probably not something I'd campaign on.
I probably should have put an extra sentence at the end to explain what I mean by the line you quoted, but I guess I didn't think people would read it as "bootlicking horseshit." In fact, I'm sorry to say I think you've read it exactly backwards.
I meant to emphasize: the issue is not my particular upload of Apollo 13 audio, which is obviously also available from a million other places. If you read the thing and think it's about my complaining that this particular audio is taken down, that gives SoundCloud WAY too easy an out: they just comply with their own policies, maybe expedite the process for a (1) former employee who (2) works in copyright policy and (3) got the dispute to the top of Hacker News, and then they can wipe their hands of it.
No, making this issue about any one piece of content, my own included, misses the forest for the trees. I am mad, and I will stay mad even once SoundCloud's reasonable employees doing their job flick a switch and reinstate my upload. I don't want other people to feel like they can relax once my upload is back in place. It will be back in place, but what we need is systemic improvements to eradicate the creeping permissions culture.