Yet, they aren't.
His final conclusion: There is no reason, is probably the right one. Jews don't eat pig, or rabbit, because God said not to, and that's about it.
When it comes to eating dog, the prohibition feels nearly as strong as if it came from God. It would take only a little nudge for somebody's existing dietary preferences to become scripture.
That preference might have had some other kind of more immediate necessity as well, but a lot of such cultural dictates are either arbitrary or become arbitrary as circumstances change. That just makes the cultural marker even more imperative. It would be easy to avoid pigs, say, if they were actually bad for you. Avoiding them even when everybody else is consuming them successfully shows a real determination.
I think from an ethnographic point of view, cultural reasons are perfectly plausible, in the same way some people now refuse to eat horse, veal, or indeed rabbit.
https://www.youtube.com/watch?v=Sew4rctKghY
Like most of his work he tries to research and source everything he says.
I can't recall if it was in the video or a comment, but one idea is that chickens just do it better. They convert garbage to food (and eggs!) more quickly and efficiently. You can eat one chicken but can't eat a similar sized part of a pig, which is important before refrigeration. They don't make lard which was a major use of pigs (apparently they were often grown fat on purpose for lard, not meat) but warmer climes had access to and preferred olive oil anyway, since it kept better.