Journalists, columnists, and popular figures are highly polarized: most conservatives are followed only by people who follow other conservatives. Most people who follow mainstream media (aside from Fox News) don't follow conservatives.
The people following left-leaning media (like Vox or the Huffington Post) are more likely to also follow mainstream media (excluding Fox News) than conservatives.
There have been lots of left-leaning takes on how the Trump presidency is utter chaos/a failure/sad. It's easy to see why. But if journalists aren't closely following what Republicans think, you might easily miss the support the administration enjoys, and then be surprised when they don't crash and burn in the midterms. For instance, national approval ratings for Trump are low, but support among Republicans within Republican districts is higher. Polarization/segregation makes it likelier you'll be heavily exposed to the former and disregard the latter.