Am I missing something? I thought Blockstream was about sidechains that are linked to the central Bitcoin blockchain. This would seem to be a great concept, and I believe we need more of them. They could remove the transaction pressure caused by micro-payments from faucets and gambling for example. So what if a sidechain is privately owned, at least they are supporting the public domain Bitcoin structure. Conceptually Bitcoin wallet providers create a form of sidechain, but nobody attacks them. PayPal, Visa and other payment providers are "sidechains" for fiat currencies, but again, people seem to think the concept is good, even if PayPal is a bad service.