Wow. I guess I'm more of an omnivore than I thought.
I like mushrooms and avocados. So much that I planted a number of avocados in my yard. I don't grow mushrooms for consumption, of course, but one of my favorite dishes to make is semi-chinese style Mushroom Chicken (from a Joyce Chen cookbook), with fresh, not canned, mushrooms. Canned mushrooms are OK for pasta dishes and soups. Squash and seafood (most of it) is fine too, especially mexican gray zucchini in a stir fry.
As for mushrooms, I guess they grow in compost, but proper compost is sweet smelling, clean, and not shit. Also commercial mushroom operations are carefully controlled, to keep wild spores out.
But I don't look down on those with food dislikes. It's a natural instinct, and I figure if one is starving, the survival instinct will overrule the food avoidance instinct.
I suspect a lot of food hating is psychological, but again to each his own.