I think the lizard thing was mostly about mocking his lack of human emotions and apparent awkwardness (due to choice or personality). Calling someone a “humongous piece of shit” is a rather plain and boring insult unlike challenging his humanity and lizard like behaviour.
You seem really hung up on wanting to call a person who’s Jewish a lizard person even when informed doing so is an antisemitic trope. Why is that? Can your feeble brain not conceive of any better insults?
Does yours? Would you care to enligten me with some better personalized insults? “feeble mind” and “piece of shit” arw higly unimaginative, surely you can do better than that.