The term has nothing to do with any military nicknames. Among car and bike enthusiasts, "squids" (origin uncertain) are young guys riding muscle bikes and sportbikes especially the helmetless and totally unskilled type that ride in a very stupid manner on public roads and probably cause more ill will toward motorcyclists in general than even the so-called 1%ers (outlaw types).
SQUIDs are of interest to sports car drivers only because some of them they like to challenge sports cars to races. In a straight line be warned they can easily humiliate almost all sports cars because that takes little skill when your vehicle has several times the power-to-weight ratio of a typical roadster. Some sports car drivers can beat them in the twisties, but anybody who'd race a motorcyclist not in proper gear for competitive riding (the first and most basic sign of having a clue) is just asking to be party to a tragic result that could haunt them for years mentally and/or legally.
'Nuff said about squids.