Conscience and the Moral Argument as Evidence for the Goodness of God.

[The Grand Nudger]

More along the lines of "IF morals are an emergent property, then all coherent groups/societies/extended bond-sharing species should show such patterns of behaviours."

So, when we meet aliens, regardless of their DNA/Number of manipulators/etc we can compare and contrast their 'Morals' with/alongside our own to see how things square away/match up.

I think you might be surprised to find out how similar various societies moral propositions are.  Even extreme examples of apparent moral difference often resolve into fundamental moral agreement with relatively little digging required.   That still leaves the status of moral values an open question, ofc.  Just within the set of cognitive moral systems there are multiple possibilities.

Our moralities could be broadly similar because we are the same species.  Thus, moral values are facts of an individual subjects natural predispositions - and as such subjective.

Our moralities could be broadly similar because our societies practical needs are broadly similar.  Thus, moral values are a fact of societal necessity - and as such relative.

Our moralities could be broadly similar because we have access to the same set of facts about x.  Thus, moral values are facts of those matters x - and as such objective.

With aliens...I mean..who knows. We'd need a moral translation at the very least. If they make a moral claim we're unfamiliar with, they'd need to supply us with facts about their natural predispositions, their societies needs, or the unfamiliar matter x itself, in order to determine what kind of morality they espouse, assuming they espoused one at all - and whether or not a given moral proposition were true. If they had a morality, though, and if that morality was anything like ours, I'd expect them to advance propositions from all three categories (and others).