Michael Conklin (Angelo State University) has posted What’s Bad for the Goose is Bad for the Gander: Censorship Is Harmful Whether Done by the Government or Private Industry on SSRN. Here is the abstract:
This concise piece makes a strong argument for how the principles behind governmental free speech protections are also applicable to private entities. Therefore, while it is legally permissible for organizations such as Amazon and Facebook to engage in censorship, it is generally a bad idea.