When the American concept of free speech was coined, it was valuable because you could go stand in a government owned square and communicate your message for free. It was a good balance between not forcing private companies to accept speech but still allowing the speech to happen.
Online we don't have the concept of a government run square, and so your speech can be totally stifled by private companies.
But the difference is that when you're standing in the town square shouting nonsense, your reach is constrained, your ability to reproduce your speech is low (you have to just stand there and keep shouting) and everyone knows who you are. Damaging speech just can't be that damaging. Online is totally different.
I think the argument of "Google can't censor you, only the government can" is not great because there's no gov't equivalent of the town square. But I don't think the answer is just "make Google accept all speech" or "create a gov't equivalent of the town square" is necessarily the answer either. I think we should be starting from first principles and understand what free speech is trying to accomplish and come up with a framework that helps us accomplish it.