The item they're selling, obviously. It's marketing, they can call it whatever they want. One might presume from the name and specs that it's intended to be a small and light firearm that can be used as part of a survival kit, such as for bush pilots or similar.
As for it being a pistol - perhaps you haven't noticed all the firearms lately that look mostly like short rifles, but are legally pistols? The short answer is that the receiver is sold as "other" or as a "pistol", and the weapon uses an arm brace or just a buffer tube instead of a stock, so it remains a pistol. For the long answer, do some research on arm braces and pistols.
The general idea is not as dumb as you seem to think, but it may be well outside your world of interests. Did you notice which forum you're in? Not many wood stocked deer rifles and upland shotguns being discussed here...
Last edited by Yondering; 09/21/18.
