Wait a minute, no one knows if in fact Apple is not letting it back in. As a dev, I can guarantee you that they are extremely fair about these things, and if Camera+ was to simply remove that volume button hack (that they had been told they couldn't use) then the app would be fine.
Could it possible be that Tap Tap Tap has made enough money that they are willing to try a social experiment? Opportunity has allowed them to make a big stink about this "removal" and now when they hop back on, EVERYONE is going to purchase it in fear of it being pulled again. Only, it won't.
Don't blame this on Apple, this is Tap Tap Tap's screw up. And as a person who bought a dozen or so copies for friends, I'm furious that, at least in the foreseeable future, there won't be upgrades.