The distinction is semantic, not technical. When I first discovered Bitcoin, there was only Bitcoin. Since then I've watched dozens and dozens of projects spring up. 90% of them are outright frauds. Scams. Of the other 10%, 90% of those will fail. That's just basic back of the envelope tech startup math. That leaves 1%.
So Bitcoiners say Bitcoin is not crypto and all crypto projects are scams, to steer unsuspecting nocoiners away from watching their finances go down the drain with some doomed crypto project.