My take is a bit different.

It’s about neurdivergence.

Data has troubles understanding emotion, but this poem is about a win in that regard.

It’s about two lovers or friends watching the sunset. One of them is enjoying the beauty on an emotional level. The other is enjoying it on a platonic level, because that is Data. Data starts explaining how the scientific processes cause the view, but the other person tells data to shut up, silently hinting that they just want to enjoy the moment with Data. Data picks up on that hint and stops talking to simply enjoy the sunset together. Picking up on that social que, was a huge accomplishment for data, that’s why he wrote a poem about it.

There’s no sadness at all. It’s all about overcoming you limitations. It’s a celebration.