So I tested this with steps on a crab, and didn't receive the effect of the step, and then did the same on a Wizard Skeleton.
Atomos did take the Ice Spikes, and not the steps present, so I believe that what they are actually saying is that if he is inflicted with a status ailment, himself, (E.I. Poison, Silence, etc...) then he'll pass it on. Because I stole from a Tonberry, Utsusemi, and he was still able to attack Atomos while he was summoned.