Because mum doesn’t know how to cook it properly. Just Kidding.
But that is also an aspect. I’ve made many people fall in love with mushrooms but they hated it as children. It’s mostly to do with the cook’s skill. Other than that, some things like stinky tofu, seafood etc truly are acquired tastes. They have a “revolting” stench but if you eat them cooked well enough number of times while hungry, it’ll just click.
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