Reddit allows writing about the Uyghur genocide

So do the vast majority of Lemmy instances.

when I use open source software, I don’t want to have any ties to Nazis and communists

Open source means it’s open for everyone to use and work on. Everyone is an all inclusive term. People with different views than you can also know how to code and develop. There are people contributing to Lemmy of multiple races, backgrounds, and political beliefs.