Claremont has acknowledged that Scott's monologue at the end is pretty awkward. Because the ending was changed at the last minute, he wasn't able to foreshadow Jean's decision earlier in the story, so he felt like he had to justify it after the fact via Scott's speech. I tend to agree with you that it wasn't necessary. But, given the massive clusterfuck surrounding this issue, it's a miracle it came out at all, never mind that it's widely regarded as an all-time classic.