Gluten-free vodka - someone got some 'splainin' to do

Vodka is a pretty simple distilled spirit, ethanol and water, two colorless, tasteless, totally miscible liquids.  It is true that fermented grains produce some aromatics that can be transferred during distillation, but then vodka is supposedly charcoal filtered to remove them.  But how is there gluten in any distilled beverage?  First, gluten is a protein found in the endosperm of grains; it's what makes bread dough sticky.  But proteins don't distill; they denature when heated.  Yes, a fermented beverage made from cereals may have some gluten, but to make a spirit you distill the "beer" to make a "whisky" and only heat-volatile substances end up in the finished product.  Using the idea that a vodka lacks gluten as a sales pitch is something TPP doesn't understand.  Who thinks there's gluten in distilled beverages in the first place?  This just puzzles me.  Is there something TPP is missing here?  You might as well market the vodka as cholesterol-free too, the vodka that's the favorite of really stupid and gullible people.  Besides, if they used potatoes as the starting carbohydrate, you wouldn't have gluten around to matter anyways.