Man, it's not a one-sided affair, and the liberal media bubble is not very different.The thing is that this is a far more one-sided affair than people would think. The GOP more or less went off the cliff after Bush Jr. (who, in the grand scheme of things, is more of a modern Grant than anything) tried to push the GOP to a new direction that didn't rely on the Dixiecrats and the Boomers. Problem was, the GOP effectively told him to fuck off more or less as they didn't want to change with the landscape. Then there is the problem of their media bubble making reality have no objective meaning...
Look at the "Russiagate" thing. For 2+ years, you had the media (all the big media except for conservative) pushing one sensational story after another. If you followed these stories, you knew that none of them really went anywhere; they fizzled out due to lack of real content. But the media did not report the fizzling out. This created the illusion among the audfience of these media that Mueller was closing in, evidence was building, and soon... BAM! Mueller would drop the hammer on Trump.
I knew that wasn't going to happen, because I'd been seeing story after story that went nowhere because I had been paying attention to media outside of this bubble (conservative and leftwing) who were calling attention to this fact. But the "mainstream" was completely flatfooted. Ditto, 18 years ago I was pretty sure, from reading paleocon and leftwing sources, that Iraq had no WMD, but if you weer watching CNN you would think that the case for them was incredibly strong.
This is just the way that media that target a specific audience function. They appeal to that audience's worldview and beliefs and expectations.