As @Faizal_Ali stated, that distinction is just human pigeonholing, the nested hierarchy by which we lump creatures together. Consider a case in point.
Hyenas belong to the family Hyaenidae, cats to Felidae, dogs to Canidae. Hyenas are considered more closely related to cats, but superficially, they also look pretty doggish. But what, exactly, is the barrier that precludes Hyenas and Cats evolving from a common ancestor by natural means, but allows for the evolution of say, saber toothed cats and bobcats? And further, what specific and essential two step mutations have been identified which separate cats, hyenas, and canines? Behe’s argument has nothing to do with the accumulation of single step neutral and selectable mutations. The explanatory power of the modern synthesis informed by population genetics appears robust and sufficient.