Organic Gardeners use manure on their crops. I think that's disgusting All types of farmers, including farmers who rely on synthetic chemicals, use manure on their crops. The difference is organic gardeners can't use the manure until it has been thoroughly composted.
Synthetic farmers can use manure without waiting for it to compost.
Peas, beans, clover, and hairy vetch are common green manures used by gardeners. These plants can be sown in the fall with special innoculants that fix nitrogen. When you till these plants in or add them to your compost pile, you're adding the extra nitrogen to your garden. Finally, simply because something sounds disgusting, doesn't mean it isn't highly effective. People have been using manure for thousands for years, and it has been found to be very beneficial to gardens and fields.