Where did you come up with that exactly? You might consider only giving advice on things you know anything about...
Some captive chameleons will cease to project their tongue their full distance due to a lack of use, trauma or nutritional issue. It has nothing to do with them being naturally shorter. Often this is the result of keepers using feeders without forcing the chameleon to project its tongue at longer distances, hyperextension or lack of proper nutrients. It typically is not a fatal issue. Just make sure your supplementation is correct, try to free range your feeders or make it so the cham needs to project its tongue at varying distances and keep an eye on it to make sure it is eating in case trauma is the issue.
Chris