I agree that this analogy is (mildly) insulting to veganism.

This is another example of an ethical choice that I made!

Is the harm here that is caused by being offensive to veganism outweighed by the value of sparking useful conversations about personal approaches to AI ethics?

I think that it is.

It's similar to the ethics of attaching a click-bait headline to a valuable piece of journalism. Is it OK to do that? That depends, both on the specific case and on the opinions of individuals who observe that decision.