Is a gasless MIG welder a contradiction in terms?
It is a "MIG" (Metal-Inert-Gas) welder in the sense that it does have a shielding gas for the weld - but the shielding gas comes form the flux core in the wire being vaporized during the welding process and not from a separate gas supply.
You'll note in the product listing "Requires flux cored wire " - because without the flux core there's no shielding gas.