Many of the gluten free banners are not actually tested. The celiac disease association has an official logo. These products have been test and amounts of gluten have been certified under twenty parts per million.
However these foods don’t necessarily have any proclamation of health attached to them just by that claim alone.
One can be totally loyal to celiac free and still have a very unhealthy diet.
There are celiac intolerances and these people can have a varying degree of intolerance to the product.
There are many symptoms associated with being gluten intolerances a short list; brain fog, ecxema or psorias(sic), bloating, joint pain(up to RA), gastro intestinal including but not limited to: ibs, leaky gut syndrome, migraines, vitamin defiencies associated with mal absorbtion. And the list continues.
Gluten can be found in easily 90% of regular packaged food items and anything in that amount of excess seems unhealthy. So while it is a fad there seems valid reason to be aware of it and limit intake.
I am very thankful that it has become one. It has raised awareness. Opened up the niche and now there are more products available. There are more restaurants where it is safe to eat food. The numerous food centered social or work related and even family related gatherings are less awkward.
Traveling is less worrisome because there are places to eat. Though I still endeavor to get a hotel with a kitchenette just in case.
As to animals. Yes there are animals sensitive to gluten. It can be harder to pick up on. But it does happen. Thier quality of life can be improved the change.