But the liver, stomach, tendons, etc. can be cooked in ways that make it taste good and give you some nutrient amounts that are hard to get elsewhere. I don't think multi-vitamins give you everything you need like people think they do, especially not in a way that your body absorbs it like it would eating actual food.
I don't encourage taking multivitamins either, but there's nothing in liver you can't get from eggs, regular meat, and vegetables.
There are also issues with overconsuming liver due to the heavy metal content. I've known people who got sick from jumping on the "liver is a super food" meme and they overconsuming it.
There is a vast difference between being a picky eater only eating tendies and choccy milk and being someone who eats a whole food diet and opts not to eat organs or at least skip the ones they don't like.
If you take it from an evolutionary perspective, even assuming people ate the whole animal (which they likely didn't) we're talking about 1 mammoth liver versus 25+ people in the tribe. Even if it were eaten it would be infrequent and in small amounts assuming it was divided equally (which in many modern day hunter gatherers it isn't).
To be clear, I'll occasionally eat bone marrow, tripe, tendon, and I've even had lambs brain before and enjoyed it. But fish eyeball, liver, and kidney I've never enjoyed so I skip them.
There is even initial research showing that people (even children) tend to select whole food combinations that both maximize nutrient diversity and minimize nutrient overload so it's possible if someone doesn't enjoy liver (assuming they're overall eating a nutritious diet) it's because they are getting the nutrients from other sources and don't need it.
Note also that I think this goes out the window when you factor in artificial flavorings, sweeteners, and processed foods as this is also backed up by existing research, so the tendie Autists don't get left off the hook. You have to eat actual food for this to work.
Forcing yourself to eat organs because you "should", in my opinion, is a mistake. It doesn't reflect actual eating behaviors of our ancestors and can result in issues at the extreme.
The main focus should be to eat a whole food diet, and to try things even if you're not sure if you'll like them. Try them a couple different ways, and if you still don't like them, eat something else. But also don't discount food just because it sounds gross or you're not used to it. That will likely strike a balance that addresses your concerns.