Boyfriend is currently #59 on the R&B/Hip-hop chart.
That's because it crossed over. Being #59 on the R&B charts and top 10 on Hot 100 should be a signal. It's not an R&B song because it charted in the bottom half of an urban chart.
Show me a REAL R&B song. "Climax" is the only one sitting in the top 20 on both charts.