Some people choose to eliminate gluten from their diets, others have no choice to and have to eliminate gluten from their diets for medical reasons as they have Celiac disease. They do not have a choice. Those who do it by choice annoy those who have no choice but to do it.
The movement towards gluten-free diets by choice has led to a mass misunderstanding by people of the medical necessity of a gluten-free diet for those who do have Celiac disease. Those with Celiac disease really resent being lumped in with the “fad dieters” by those who just do not understand it.
See this story: From a celiac: I don’t like gluten-free people either.