Kinematic considerations are shown to imply that the steric requirements of the title reaction will be most manifested for backwards reactive scattering, as is observed (Parker et al., Chem. Phys. Letters 86 (1982) 113). The computed dependence of the differential reaction cross section on the orientation of CH3I is progressively weaker as the KI product is scattered into less backward directions, in accord with experiment. A kinematic model with an orientation-dependent barrier to reaction and an impulsive release of the exoergicity is employed.