Their direct incentives are getting sales (and now clicks), which doesn't appear to be highly correlated with accuracy. Additionally, my experience in college was that it wasn't the best and the brightest going into that field, though I deeply hope that it was a skewed sample, and believe that there are many deeply intelligent people working there.
However, I think it likely that many people are not drawn to the field for the pursuit of pure objective truth, but because they have a particular agenda and want to enlighten the world with it.
There is a quote about a logical fallacy that I can't quite remember, it goes along the lines of the following: You read an article about something with which you are deeply familiar. You laugh to yourself at the childish misconceptions of the journalist. You then turn the page to something you know little about, and assume that everything that is written is true. That doesn't make sense.