Agreed. I always heard cooking acidic food in cast iron was bad not because it’s somehow bad for you, but because it can ruin the seasoning.

Thirty minutes isn’t a long time to simmer tomato sauce though. Well seasoned or not, you’ll still get some iron leaching into your food too, but that’s a good thing and the trade off makes it worth it. I choose not to cook acidic foods in my cast iron because I find I have to reseason it more often.