Chameleons are insectivores, not carnivores, and excessive animal proteins in the diet lead to renal failure and gout due to excessive uric acid buildup in the blood from protein breakdown. Animal proteins are different than plant proteins - they are not broken down in the same way. Gout is incurable in chams and extremely painful - it's a death sentence. Renal failure is a death sentence as well.
That is why. It is important to know the possible consequences of what you do. Not saying that it will happen immediately, or in every case, but it can and does happen with inappropriate diets.