I'm confused by your definition of "freedom of speech". You have the freedom to create whatever art/game you want. The dev could have created the game if he wanted to. Freedom of speech does not require Steam to host your game on their platform, however.
Not to mention, if you are a huge champion of "freedom of speech," why are you so upset that the community is "bullying" (your words not mine) when they are also expressing their views through their freedom of speech? So the game dev is protected by the freedom of speech but not the community expressing dissenting views?