That's not the framework to use.
What's happening is that the government can allow "free speech" to criticize the government because they can just leave you alone. They don't have to spend money to leave you alone. Arresting everybody that criticizes the government means spending money for agents to round up citizens and also spending more money on prisons to hold dissenters.
The other form of "free speech with zero negative consequences from private entities" is impossible for a government or a society to provide for you. I'm not being hyperbolic -- it literally is impossible to give you that type of freedom. That type of of "commercial free speech" has a cost and other citizens are not going to pay for it. This leads into my response to your other statement...
>Does using Google products qualify my relationship with them as an association? In the same way that me buying you a cup of coffee is association?
You are misunderstanding how Freedom of Association affects "freedom of speech in a private business".
Using Facebook as an example, consider that some of their biggest advertisers are Coca-Cola, Proctor Gamble, and Samsung.
Let's say you want a law that forces Facebook to host posts (text not photos) espousing the benefits pedophilia. Pedophilia text is legal. Facebook user is happy that his legal viewpoint isn't deleted. This is now "free speech in private space" nirvana right? Not really. What the proponents of free-speech-on-private-platforms didn't consider is that there's no parallel law that forces Coca-Cola, ProctorGamble, Samsung to keep paying Facebook for ads. If Coca-Cola marketers say, "we don't want to run ads on Facebook that has child sex posts", they are free to abandon that platform and spend their ad dollars elsewhere. (Freedom of Association). The so-called "private treated as public space" that people wanted to spread alternative and marginalized viewpoints won't exist because nobody else wants to pay for it. ((The users of Facebook is also an "association" and if they freely leave the platform because they don't want their profiles intermingling with pedophiliacs, that will further erode Facebook's value.)
Freedom of speech on private platforms has a cost and this is why the society can't give it to you. Society doesn't want to pay for all viewpoints.
Some may think the obvious answer to the paradox of Freedom-of-Association vs Freedom-of-Speech is to collect taxes for a government-sponsored "public social network". Such a platform wouldn't be dependent on voluntary advertisers and their discretionary dollars. Unfortunately, that won't solve the problem for free speech either. If you think it through beyond the surface level appeal of such a platform, you'll see why it won't work.