As a casual cyclist commuter, I can coast probably 100 meters after stopping pedaling. It's not the slowing that is hard though, it's the anxiety of needing to exert a lot of effort to get back up to speed. From that angle, I'd posit that cyclists may be doing this out of laziness, while scooter riders don't have that same mental/physical cost to fear when they stop.

That said, I don't run lights, and am just as baffled how some cyclists will barrel through a red light at intersections without even slowing down...