Every time someone brings up social good, I keep wanting to know what that means. Can we have a truly objective definition of 'social good'? Or is it entirely dependent on the individual person's definition of what that means to them.
I agree that it's not a sufficiently precise term, but I think it's obtuse to suggest it's so ambiguous as to be deceptive or obstructive to discussion.
How's about: an act that is socially valuable has benefits, immediate or otherwise, realized by parties that aren't directly involved in the transaction.
Eg, a blackjack dealer's labor probably only matters to her players and her boss, but a cancer researcher impacts well beyond that. Both can be lucrative, but one is clearly more socially valuable.