I don't know the exact particulars about that situation, but that aside, knowing what I do about the mechanics of these types of things, I'd have to say that Ricca was definitely NOT any type of informer or cooperator. I'm sure there were conversations held between Ricca, Cerone, Accardo and other top figures in their administration who vetted and pre-approved such a move for the "greater good" for the Outfit.
But if, as you say, a rat is a rat, then imo there is no excuse for Ricca either. If "for the greater good of the organization" is a "justifiable" excuse for giving someone up, then someone could argue that other excuses you listed above would be "valid" also.