You are changing the argument, two-fold in fact.
First, that Ginsburg was confirmed unanimously has nothing to do with his statement that he'd never nominate her, but voted for her. Now it does mean that he can say that she was not a controversial pick and everyone voted to confirm. That's a valid argument. But it is not what you said in the original post.
Second, that there is a lot of scholarly debate over exactly what "advise and consent" means is no answer to the criticism that he cannot say he wouldn't nominate her when he voted to confirm her. The criticism he gets for that is that he seems to be saying she is obviously not worthy of the post and yet he voted for her.
To be honest, I don't think much of this issue. For one thing, I doubt he meant that he thinks his vote for her was bad. It was based on the info he had at the time and everyone voted for her so he can't rellay be singled out in regards to her. For another, it seems to me unlilely that if McCain is president he will go real far right in his nominations. Heck, the fact that he would likely appoint moderates is a criticism he is getting from the right as much as anyone.