I commercial fished when I was in my 20s. I don't have any idea where you came up with that nonsense. "They are dirty." Lol. So they are bottom feeders. So is halibut, catfish, flounder, halibut, and sole, not to mention crabs, lobsters, clams, mussels, oysters. Oh, and you missed eels.
Perhaps you are just another Western clean-freak, obviously one who is afraid of fish and tasty crustaceans. With the exception of catfish and eels (don't particularly like the taste although smoked eel isn't too bad) I love all of the above.
"They're DIRTY."
Pfft - your loss. More for me.