I don't begrudge Cypherdoc not going into detail on dismembering these, because they aren't all that substantial as critic defenses go. I don't know if it was sincere claim that these "debunk" all concerns for all people reading this or if that is just baiting.
Mistake 1 : Sidechains can protect the value through merged mining.
If at some point in the future, there is a particular SC that consumes the bulk of bitcoins in circulation, there is a non-zero risk to Bitcoin that there will be insufficient bitcoin transactions to support bitcoin mining in the later days. It will have ended Bitcoin (albeit presumably for something better). People are not always right, that's how we got to where we are with pervasive central banking
The bolded is what I cannot comprehend.
To suggest such a thing would happen is essentially to suggest that a sidechain would be created that carries all of Bitcoin features and more. So essentially, what you are speculating is that a sidechain could be created that is so innovative it removes the need for the Bitcoin blockchain.
But it begs the question : what features could be so compelling?
Anonymity? My opinion is this should be user-defined?
Faster transactions? This comes at the cost of network security
If such a chain emerges that offers these features in a user-defined manner without any tradeoff, then why should we not welcome it with open arms?
This one is simply wrong. Further, it makes several claims in succession that are not entirely related. These are specifically a risk that SC do introduce. In the same way that if physical bitcoin were what everyone wanted, and we traded those instead, there wouldn't be any Bitcoin TX fees. These do have greater value in the free market than electronic bitcoins. There is no peg, what there is, is inclusion and embedding of btc in another block chain which is separately traded off Bitcoin's block chain.
Analogy to physical bitcoin is asinine. There are transaction fees for every sidechains transactions and every miner is able to process and profit from these. And no, as I have stated in my previous comment, the features of a sidechain are user-defined and so I don't believe it is correct to assume "there wouldn't be any Bitcoin TX fees". There are several reasons for why I would prefer my transaction to take place on the main chain. I don't need anonymity or faster confirmation time for every transactions.
This is your mistake.
SC assures neither of these.
SC does not assure any preserving of the Bitcoin ledger.
The additional features are not in the Bitcoin ledger, they are on the SC.
They are "possible" effects. You are using the word "can" here and pretending that it means "does", and suggesting that this answers the concern. Many people do this subconsciously, it is human nature. Don't feel too bad about it.
The essence of my argument throughout this thread is that the real innovations in sidechains are the utility of 1:1 two-way peg to make additional features possible WITHOUT disrupting the ledger/affecting the scarcity.
You can argue all day that altcoins could be created booted on top of sidechains and that they COULD be a danger to Bitcoin but this is not something that was enabled by sidechains. This risk (altcoins) was always present.