I've said it once, and I'll say it again, it was a touching line that most people don't seem to be able to grasp. It's not supposed to be funny or stupid, it's Roxas in his most desperate hour. The ice cream moments are what defined their friendship, and in a moment where Roxas is losing his best friend, the only words he manages to articulate is a plea about the ice cream, something that, while trivial and even silly to most, was beautiful and amazing in their friendship. It's in that moment where you truly see how sad and desperate Roxas is. I think it only makes sense that he doesn't say something deep or meaningful, but that he blurts out what truly meant most to him about their friendship, simply enjoying laughing conversation on top of an ice cream tower. It's a powerful moment that says a lot about the true value of friendship, and I think it's unfortunate that most people overlook it as a stupid line that ruins the moment.