Is Moneta one of the private companies working with Blockstream?
"To my mind, Zerocoin and Zerocash are the low-hanging fruit of sidechains. Just transfer your bitcoin to a sidechain that implements one of those protocols, and voila, instant Bitcoin anonymity; you can send or receive money while maintaining mathematically perfect privacy."
Is it associated with XMR in anyway?
No, and watch out for these guys (Moneta). Same guys as:
https://bitcointalksearch.org/topic/zerovert-first-truly-only-anonymous-coin-with-zerocoin-mandatory-upgrade-846471
&
https://bitcointalk.org/index.php?action=trust;u=391031
This looks to be an actual privacy-centric side chain project, not an altcoin. Unless you have evidence to the contrary.
How come we can't just make XMR the privacy side chain? Some technical reason?
[1] https://news.bitcoin.com/first-implementation-zerocoin-released-introducing-moneta/, enough evidence in that article.
[2] If we make XMR the privacy sidechain we inheret Bitcoin's security model as well. In addition, I am not entirely sure if there are already viable methods available to secure the sidechain itself.
Moneta has Roger Ver as an angel investor. Blockstream has $60mil+ to develop side chain technology. If it isn't XMR it'll be someone else I should think.