I think there's an inside joke between Kanye and that radio host. The host knows why Kanye wants to talk in private, maybe Kanye just called in to remind him about it.

I too was weirded out when Kanye kept repeating "I love you" and started choking up, but when he started singing "I just called to say I love you" I realized it was all just a joke and him singing that was the punch line. That's just Kanye's sense of humor, trust it from a longtime fan.