Is it maybe that most people have checked out too and only a small but loud minority is addicted to all the nonsense? On Facebook it seems it's only a few people that constantly post web links or engage in flame wars. Most people I know are very quiet.
I know someone who only ever posts about gardening, and yet I know for a fact she reads almost everything people post. Her husband on the other hand is constantly posting and commenting on far-right posts. They are still influenced the same way, they just express it differently.
That's by design and intentional. Anything you say online can be used to convict you in some obscure court of public opinion where your viewpoint didn't align with the mainstream viewpoint.
(This, I think, is the real lesson of computing in the modern era, that subjects will not object to being surveilled if they don't notice it. The abstract argument against it is predicated on possible future action, and the inability to stop it.)