The best line of defense against this nonsense is education, free and of a very high quality. Absent that people will be pretty easy to manipulate. So whenever you're faced with a problem like this I would argue for better education rather than for some kind of control over the media, the liars should die out because nobody believes them anymore.

Given how incredibly entrenched some power structures based on lies are it looks as if my plan is mostly failing. Education budgets are being cut left right and center and the quality of education has been steadily trending down since ~1950 or so.