Exactly. As annoying as it is, this isn't a breach of DMCA in any way, shape or form - it's YouTube saying "it's more important for us to make the record labels happier than it is you". And, for better or worse, that's their perfect right.
It's not. The First Amendment guarantees you a voice, but not an audience. Youtube has every right to tell you to sod off if they don't like your content for any reason.
FWIW, I upvoted you back into the black, since I thought your intention was clear. Lots of people seem to make this mistake, that somehow the first amendment means that private companies aren't allowed to censor you.
It would be disingenuous to suggest YouTube is not the de facto video sharing site. If they censor something, it's a big deal.
It's the same thing with Amazon, Google, Twitter, or iOS. There are ethical implications if you are one of the major conduits by which people communicate and disseminate information, regardless of your status as a private or public utility.
Legal? Who cares. Ethical? Maybe. A good idea? No.
You think Twitter doesn't feel responsibility if they close out an entire country from their service?
You are pretending there are lines dividing sides that are black and white.