I don't know what you mean by "free". Of course, a business owner is free to direct their business as they wish within law. Would I like it? No. But businesses are rarely ideologically neutral, and they often reflect the ideals and world views of the societies that created them. As Twitter is a Western company, it reflects Western notions, so I wouldn't be happy when it starts reflecting Saudi world views, but if it does, I guess someone will start another Western Twitter. If you want Twitter to be a public infrastructure rather than a private business, make it a government-owned company.