I did hear the segment and was puzzled. He clearly is aware of the BC issue and has made a decision not to discuss it, so to play that clip and then just move on seemed a little unusual for the Great One.
I can only offer my opinion as to why he played the clip. It sounded like a good natured "tweek" the same way Rush slips a "birther tweek" in on rare occasion. Neither is a birther, but on the other hand, since the majority of their listeners are conservatives, and since birthers are more than likely conservatives, what would be the upside to publicly ridiculing some percentage of their loyal audience?
Among their loyal listeners, this is a divisive issue, and I'm sure they think that discussing it at length and in depth will further polarize their audience, fanning the flames of an internal party squabble for the amusement of the left-wing press.
I just don't think there is a good reason for Levin or Rush to bring it up.
JusMyOpinion...not even worth the price of the cover charge.