Actually it can be helped when everybody agrees that some information must be known by everybody. Communication campaigns, making it a subject in schools...
So the problem uses to be that there are opposing sides trying to beat each other. OK, that's obvious, isn't it? But come to think of it, is society so divided that most people's interests conflicts with somebody else's?
I understand that there are diverse interests dividing countries or continents, but often differences inside the same country seem to be artificially amplified and fuelled.
Both of those are basically so delayed and holey that you can forget using it for anything but the most basic points. Just look at how bad some people are at math and that's something both essential and taught extensively for basically the whole time one is in the education system.
This sounds like Dawkins conception of a meme: an idea small enough to replicate as a whole without error.
Communicating with more than one person at a time requires dumbed down slogans and short bits of summarized information. Nuanced long form communication is a luxury that can rarely be afforded.
I guess it scales on text with a specific crowd (HN).
Nuance requires representing uncertainty and is higher complexity from accounting for multiple special cases. Placing more cognitive load and attentional demands on receiver.
Human communication is lossy and decoding can be non-trivial inference. Given that everyone comes with differing priors, the more finer grained and complex details are required in reconstructing message intent, the more likely it is to be misconstruected. Failing to attend to a single core detail can rend meaning.
At scale the chance for errors to propagate without correction increases.
Getting rid of fine grained details and communicating a lower entropy message inline with a crowd's biases also ensures it's more likely to survive in a form close to original intent. A good manipulative orator focuses less on truth or content and more on minimizing mismatch between receiver mental states and orator's directional preferences.