The compatibility chart is for the headphones, not for the ears. They assume that people buying those tips already have experience with silicone tips.
FWIW, since we're kind of roundaboutly on the subject, I can't really recommend custom earplugs/earbuds. IME, corded earplugs of any kind - which would include earbuds, even if they're wireless they'll be connected physically to some kind of external structure - the cord picks up vibration not only from extrinsic sounds, but from any time it brushes or presses against clothes, hair, or helmet and carries it right into the ear. Uncorded earplugs for noise blocking only, IME are nice for air travel (since they don't seal pressure inside the ear canal) and if you sleep on your back. But since they work by covering the ear canal, not by sealing it, if the outer surface comes in contact with anything, like if you sleep on your side, it both puts pressure on your ear canal and carries noise inside. Walking around, for some reason the noise of my own footfalls is deafening, which I don't have that experience with foam plugs.
Speed comes from what you put behind you. - Judi Ketteler