What I'm hearing you describe is that the token used by a Sidechain is not one iota different from any other Bitcoin, except perhaps that its latest output script includes some new weird feature we haven't seen yet. It's like my sending you 1.0 Bitcoin through a vanilla BTC transaction and you telling me that I now possess 10e8 Satoshis, which are different that Bitcoin but always redeemable for Bitcoin pegged at that rate.
If tokens being used by Sidechains are permanently pegged to Bitcoin, and we assume merged mining, I withdraw my objection to the concept, and would instead direct my criticism toward how the concept was presented and its seeming suggestion that Sidechain tokens might one day detach and rise in value while Bitcoins potentially fall to zero.