Pennsylvania, Michigan, and Wisconsin are not leftist strongholds, where "infighting" might allow the Other to win, but people prefer the narrative that "Bernie Bros" ruined our beautiful democracy. Clinton got millions more votes, but it didn't matter. The Electoral College turning it doesn't fit the narrative they've been fed that people further to the left are responsible.
You're right about polarization though. Less than 100k votes wouldn't matter if the country wasn't divided right down the middle. Choosing the future of our country shouldn't be a matter of who can influence a coin toss more.
My very first check of that assertion has a fully "True" rating of 20%[1]. And if you count the entire true spectrum it's 73%. And there is not a small sample size. I assume your statement is only regarding the current executive branch?
I also tried a spot check of the Congress, but my very first check also failed to meet your criteria[2]. The problem with this is that it undermines your entire point. The executive branch has the most strained relationship with objective reality, and that stems from the demands of the current president. They're basically forced to lie for political reasons because the truth is too damaging.
[1] https://www.politifact.com/personalities/barack-obama/ [2] https://www.politifact.com/personalities/mark-warner/
Off the two democrats congressional Leaderships, Nancy Pelosi has 14% and Charles Schumer has 11% in the True category. This in contrast with the republicans that has 12%, 0%, 10% and 5% (trump).
From personal experience the issue we have with fake news is not caused by a president. It was the polarization from the 2016 election, which has resulted in people valuing the narrative over facts. Nothing was a clearer example to me personally when later that winter as I was participating in a conference located in Stockholm, which had a track title "Fake News", with an invited keynote speaker who was a previous board member of the wikipedia foundation. The keynote talk was made to present a narrative that media had failed to present information to the voting population about trumps scandals, and as evidence there was a image from a study showing survey result about what people knew about each candidate and their scandals. The conclusion was that if media had done their job then obviously the election would had ended correctly rather than electing Trump.
The numbers were extremely biased against Clinton and fitted the narrative so perfectly that I got a bit suspicious. Looking at the recording of the talk afterward I noticed that the evidence had a reference printed inside it. A moment later I had the paper itself, and what do I find above the image? The researcher explicitly saying that anyone reading it should not draw any comparable conclusions about the numbers as the survey operated during a period of 9 months. The researcher noted that if they had done a new short survey closer to the election date then the numbers would look very differently. It pretty obvious that people can not answer a survey with knowledge of scandals that occur in the future.
Fake news will continue as long we try to make facts fit a narrative, rather than first looking at the facts and then construct a theory about the world.