What happens is the information is creatively formed in the mind of the receiver, by the receiver, in all cases.
In other words, people form an explanation for the observation in their minds and judge it compared to other competing explanations.
So instead of the post-truth, doom-and-gloom world that you fear, another possible outcome is that people get better at forming or identifying good explanatory knowledge. In other words, the bar for what you call truth actually goes up and people get smarter.
An example of this happening would be door-to-door sales people. They basically no longer exist. Because people learned not to answer the door when a random person knocks.
The old explanation “someone I want to talk to is here to see me” got replaced with a new better explanation of “some time wasting stranger is probably at the door.”