That reason being, they're not very tasty.
I just got some as street food in Thailand. It's been a while, but if I recall correctly I had:
Fried Ants: These basically tasted like the bottom of a KFC bucket.
Grasshopper: You had to pull apart the body and the head like a crawfish. Don't recall the taste.
Big maggoty thing: It didn't taste very good. It wasn't fried, tasted more like stewed or sauteed- moist but not mushy.