It's sort of like lowering Facebook's "threat surface" with respect to privacy laws. And, IMHO, that's really a Bad Thing. I'll give tptacek some credit: existing privacy laws really are inadequate. But I'll still argue against removing what little protection we have, just because we're going in the wrong direction.
That said, I'd like to see more arguments against the actual provisions of CISPA. I didn't see domain seizure anywhere in the law, for example, so I would greatly prefer it if my fellow CISPA opponents were more careful to advance the best arguments we have against it, not just the most popular.