I think it's mostly just the difference in goals. Programming has one clear goal; describing logic rules that both human and machine can understand with the le

I think it's mostly just the difference in goals. Programming has one clear goal; describing logic rules that both human and machine can understand with the least room for misunderstanding. Simplicity facilitates that. Natural languages serve many purposes. When used purely functional simplicity is still wanted. Instructions for example are written as simple as possible with limited vocabulary, not that different from programming. But we don't speak purely for functional reasons, it's also entertainment, expression, play, emotion, for those you need more options on how you communicate something. For example a story told in its simplest form is usually not very effective. How it's told makes it interesting, entertaining and/or evoke emotion. That requires more options and freedom.