There are plenty of other people working on building distributed-exchange coins from scratch. Counterparty made the explicit decision not to be one of those guys. To put it simply, "built on Bitcoin" is THE central idea behind Counterparty. If you don't agree with that decision, you should be backing the other guys.
Except... it's not built on bitcoin. That's exactly the gripe of myself, jtimon, and others I'm sure. Counterparty does not interoperate with bitcoin scripting. You cannot have bidirectional transactions between the two. Counterparty rules are not validated by bitcoin nodes. Lightweight clients can't rely on most-work as an indicator of validity. Counterparty is built
separate from bitcoin. If I take a bible and start scribbling in the margins, do I get to go on a pulpit and claim a biblical foundation for my scribbled theories? No, it has no relevance.
Counterparty transactions are scribbled in the margins of validated bitcoin transactional data. So what? Bitcoin does gain from this. Counteryparty doesn't gain from this, any more than they would from a fully merged-mined datachain or any other equivalently powerful proof-of-publication sytem. And Counterparty
could be doing much better by having miners which validate its transactional data.