In the old days, before cleats that fit and locked into pedals, people used "toe clips."
Clipless pedals are ones that don't have clips, and you'd think that would be any pedal you don't basically tie yourself into. But "clipless pedals" was invented (as a name for them) to mean pedals that hold onto your foot, but don't have clips.
So your SPDs are clipless.
It's like how you park in your driveway and drive on a parkway, or pineapples aren't apples and don't grow on pine trees.