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.
But saying he's a reptile is way too cool and badass. Lord Voldemort can be compared to a reptile.
Zuck is a tiny, pathetic piece of shit who throws tantrums when he loses at board games. He's not an evil genius mastermind, he's a metastasis.
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?