Peter Vessenes is the one who got this ball rolling, and he's one of the founders.
He talked about tainting a couple times. That's it. And given that he's a lawyer and not an economist, he probably didn't realize how terrible the idea was at the time. The foundation has never, and likely will never, endorse tainting.
They will be, at least any of them under FinCEN jurisdiction.
Exchanges are already a lost cause (even the ones outside the US), precisely because they receive tons of Fiat money and integrate directly into the regular financial system. FINCEN has not claimed jurisdiction over regular merchants, who accept bitcoin as payment.
Even if we stop this initiative, though, they'll just start over and just not announce it next time. US law allows/requires them to do this.
The data gathering aspect, yes. But they can only share the information that they actually know about the buyer. Digital goods merchants probably only know your email address, not your identity. But then again, the NSA can get the info even if no money changes hands at all. Hell they can get your info regardless of where you buy your stuff, because most of the shipping companies are US based, and therefore their shipping records are accessible to the Govt. This is unfortunate, but has little to do with Bitcoin
The really dangerous part of the CoinValidation initiative, is to make merchants reject funds that aren't sent from an address with an associated identity. But that can't be done in secret, because they need to tell you that you need to register and give them a bunch of info.
Again, let's not panic, I suspect that this idea will be killed off pretty quickly. We don't need to start punishing US merchants in advance just because they might decide to cooperate. We can always do it after the fact, and avoid hurting people who are on our side (despite differing tactical approaches).