The Revenge Doctrine is undoubtedly just. The Moldavi doctrine is not really something you can assign morality to. You can say their enforcement of the doctrine is just (the don't just shoot first and ask questions later). But is it "moral" to not allow an alliance to colonize red? Sure, if you really need an answer. There are a dozen other teams to occupy, most of which are superior anyways (in terms of trades, unity, etc).
It would be immoral if EVERY team had such doctrines, however.