RAP? Would like some opinions

I smacked a hornet's next on Facebook in regard to a Rap entry winning the top song at Grammys. I said I thought "rap song" was an oxymoron. Katy Bar the Door! Lots of fun, some deep thinking in regard to what music is, etc., but no consensus. My problem is that rap does not satisfy my notion of "song." (Wikipedia notwithstanding.). What say ye?