Promoting free speech would be efficacious as a tool to stop such people if it had any "staying power" to linger on as a defense-in-depth tool to fight them after they assume power - that it would take a while for them to get rid of it. Unfortunately, I believe it could get shut down almost immediately.

The trick is simply keeping people like that out of power.

I guess we all imagined that multi-billion dollar advertising industry then...

I need more context or detail to understand the point you a trying to get at. I really do, because otherwise I am just trying to guess what you mean, or even how it correlates to what I said at all. Without further clarification, it seems to be tangential to me.

Who is "they"? Who apparently represents all global advertising interests, and also represents all who desire to censorship for any reason?

I still don't understand what you are saying. When you say "Who is "they"?". Are you saying Google and other tech giants? They have huge advertising networks. But that is a total guess since what you are saying is still very unclear. It looks like you don't want to be clear about this. I'd really prefer you to just say it, rather than all this cryptic stuff.

But since you go on about advertising, that is a way for groups that want it, is to be able to force people to listen to their message. This robs people of their agency to listen to what they choose to. Censorship also doesn't allow people to listen to what they choose to. This makes advertising and censorship very alike. They both result in a persons loss of freedom to choose what information they get.