The media can desensitize one to more than the grotesque or extreme that the world has to offer. Just about everything the world has to offer can be dulled, pulled out of focus when one is constantly bombarded with it by television. News stories that might be history-defining moments become muffled by the 24-hour news cycle, all but drained of their impact through repeated exposure. Watching the talking heads prattle on endlessly about stories regarding political figures, attacking every potential ramification of a social media post begins to wear one down until the only thing one is left with is a numb void, one where an emotional response had once been.
There is only so much time in the day that one should dedicate to topics outside of their control, and media tends to push up to that boundary and then crosses it without looking back. For all the effort that news organizations put into communicating stories that the populace should care about, very little seems to be devoted to learning and adjusting how that message is received. What matters is ratings, and as long as eyeballs are on that ad in the commercial break or that shares the page with the story, consequences be damned. Sure, outrage still exists and people still support their pet issues with fervor, tweeting whatever appropriate hashtag is going to get them the most upvotes to go along with the selfie they take while attending a rally.
One strange reaction that seems to arise in some is complete rejection of the information provided, which can lead one down a rabbit hole of conspiracy theories proposed by similarly-minded people. If one manages to avoid being oversaturated in the information age the methods these organizations employ could be effective, reaching everyone at the time of day they are receptive.
Different people have different levels of tolerance when it comes to desensitization, and some may never suffer adverse affects given how much exposure to a subject they get. Too much of anything can have negative effects, and it is up to the audience to mitigate them by moderating media consumption.