"Appeal to nature" isn't a logical fallacy, it just assumes some things about how things should be. You might disagree with those assumptions, but you, too, have beliefs about how things should be.
In which case it would be much more honest to say "I think this is good or bad" or "these are my values and they are not subject to debate" rather to propose that thing you like is the natural state of affairs and offer that up as if it were a proposition that you were debating. Or worse, the null-hypothesis from which some nebulous burden of proof is assumed for the opponent.
In other words, it is a dishonest strategem which relies on the other party making the logical fallacy that the natural state of affairs must be good, or that a burden of proof lies with them, instead of recognizing this as the sleight-of-hand that it is.
So I think GP was just being polite by calling it a logical fallacy :)
