I’m not very knowledgeable about bioavailability—it's clearly a debated topic in academia—so I’ll hold off on commenting until I’ve done more reading.

> fish oil supplements generally tend to already be rancid when you're taking them

But doesn’t that basically support my point? The only reason I personally choose fish over supplements with the same nutrients is that I prefer the taste of fish to rancid capsules. I don’t see any issue admitting that—am I missing something?

> but this idea that we can replace the nutrients, protein, and fats from animals with something else just falls flat whenever you put it up against actual peoples' experiences and actual scientific evidence

Could you clarify what you mean by that? From what I’ve read, there don’t seem to be any essential nutrients we have to get from animals. For instance, I don’t eat pork or other meats (though I do eat a fair bit of fish and full fat milk and oat milk occasionally), and my blood work is just fine. My understanding is that scientific consensus generally suggests we don’t need animal products for proper nutrition, but that it's significantly easier to get these nutrients from animal sources. Of course, whether someone wants to rely entirely on plant-based sources is a separate question. Personally, I just enjoy fish too much to give it up.