Why do people say that I shouldn't feed crickets to my pet?

Crickets have gained something of a bad reputation in the reptile community. Many people assert that they shouldn't be used at all — mostly because of misinformation related to parasites and low nutritional value. However it is true that they are more delicate than other insect feeders, and tend to have a certain unpleasant odor.
The facts are that crickets are easily gut-loaded, easy to dust, inexpensive, readily available, and nutritious, making them a suitable part of any pet's feeder insect rotation.