I agree. He granted people rights to use and distribute his software. It's unreasonable of him to attack people when people start using it.

I'm well aware there are some complications with open source licensing, in which many businesses profit off free labor without giving anything back. However, this isn't what happened here. This is a case of volunteers working to ensure that Home Assistant would work on NixOS. The upstream author came anyway and demanded that NixOS not use his software, refusing reasoned dialogue and instead throwing thinly veiled insults.

If many consider this acceptable, then the purpose of open source licensing would become moot. I'm glad this doesn't seem to be the case here.