Is Coeliac disease really that prevalent that they are worried about a gluten-free version of soylent? (I personally know one person with this condition but even he is annoyed about how everyone is going gluten-free.)

Its a buzzword to go gluten free, so why not capture as many sheeple as possible?

It should be logical that the presence of people with a legitimate condition + the presence of people who erroneously think they have that legitimate condition != overreaction on the part of a given person that thinks that they have that legitimate condition.

Being sugar-free and carb-free are also buzzwords, and for sheeple, right?

good point

GF is not necessarily a good marketing buzzword as most gluten-free products are more dangerous to the general population in general. For example, gluten starch is replaced with tapioca, rice, and potato starches, which have higher GI, i.e. they increase your diabetes risk.