I think that's a different situation than the 0L visiting a class for ASW and volunteering to answer a question. Would have been tough for you to just say "lol no thanks prof."
Even at HLS ASW #1, one kid just went in on the negotiation clinic spouting off about ethics and moral pluralism to the entire 400 student audience. Talking about value positions and basically taking his philosophy class final paper and repeating. He appeared to think he was so ground-breaking and thought-provoking
I mean, in fairness to that guy (it wasn't me, I promise), the professor in that case was soliciting opinions on how each group reached a consensus. I know that my group (not with that guy in it) spent the vast majority of our actual debate time talking about deontological justifications for choosing to randomize who we saved. We simply happened to have a group where all of our were at least nominally interested in and informed about those topics. I don't think that discussing that is any less valid than, say, the groups who talked about scientific principles behind drug testing because they had someone with a background in pharmaceuticals.
Now, maybe I'm misremembering and it was worse than you described here. I definitely could see myself rolling my eyes at someone who actually tried to moralize to other people, rather than just stating the moral consensus that the group reached. In that case, mock away.