"but why did they do the rhyme?"
A lot of us have wondered about that for years too!
Actually, I think the reason it got stuck in is because from a technical standpoint it helps speed the pace of the episode because if it had been done in the realistic way we prefer we would have needed Starbuck to explain the plan in precise detail without being set to scenes of the plan being implemented, or had some awkward expository dialogue during the implementation that would have come across awkward on the screen.
Sometimes the things that can leave us baffled from a plausible story-telling standpoint are the kind of things that the demands of producing a tightly constructed 48 minute script end up imposing on the story, and I think the whole silly "singing" sequence would be near the top of the list in that category.
