Why is proprietary-licensed software unethical?

Kimi K3 itself isn't FOSS. Speaking of reciprocity: Fireworks is presumably paying Moonshot serious money for the right to do what they are doing here, since Kimi's license[0] excludes commercial inference providers (such as Fireworks) from gratis use. It requires them to: "...enter into a separate agreement with Moonshot AI before using the Software or its derivative works..."

[0] https://huggingface.co/moonshotai/Kimi-K3/blob/main/LICENSE#...