who says dont use them? the only reason i can see is if your digging them up they may have internal bacteria but if you rinse them in water and squeeze the poop out then your eliminating all that and your left with a healthy vitamin rich meal for your fish
yeah earth worms are good! I feed my three little pbasses them. I squeeze the poop out of them and stuff it with omega one pellets haha I do this because they won't take the pellets straight so I sneak them in using the worms.