I'm not sure this is a case of responsible vs full disclosure. Obviously, we don't have full disclosure of the issue yet. However, that doesn't mean we won't have it on the 4th when Postgresql said they would be releasing their fix.
To some degree I don't think "full disclosure" and "responsible disclosure" are very useful terms since they have so many different interpretations.
But looking at this particular practice, I'm not sure there's been much debate in the open source world about this practice of pre-notification to vendors/large installations.
In my personal opinion I think it's absolutely necessary. Most open source users depend on binary packages provided by someone else. Unlike a closed source model when everything happens within a single company. Even then I'd be surprised if some of this doesn't happen with large customers with closed source software.
So in practice I don't think it's anything that doesn't happen with just about all heavily used pieces of software. It's just that this case happened to be more obvious this time. Largely because Postgresql closed their public repository in order to package the fix and announced that they were doing so.