Respectfully, I don't even know if I would agree with that on a number of levels. Even the existence of one example should have stopped you in your tracks already, because that's all it takes to demonstrate as a principle that bias doesn't work that way. But I also think those are just the tip of the iceberg, and there are broad swaths of widely believed claims that are fundamental to people's sense of their own political identity also in exactly this unfortunate category.
On the left side of things some (not many but some) there's a lot of apologizing for and minimizing of the horrific human rights records of the U.S.S.R. and China, some degree of falling for present day pro-Russia misinformation, and uncomfortable truths about the party's own closing ranks around people with a history of sexual abuse. And on the right there's a lot of deep-in-the-bones denial of evolution, or historical revisionism about their ties to the "party of Lincoln", or who won the 2020 election, and it's expanding every day to include new topics like prediction of hurricane paths to provably wrong information about nutrition, and so on.
I would say it's so omnipresently pervasive in the present day that it's impossible to wave away and is increasingly fundamental to explaining and understanding polarization.
I think we are maybe talking about different things. Liberals and conservatives have wide platforms that cover hundreds if not thousands of topics, the thousands and thousands of policy decisions needed to govern a full society. It's not just 3 or 4 things that get lots of attention at any given time, because we can shape any narrative we want without looking at the full picture.
I can say Bernie supports tariffs so he is a conservative and Trump is giving student loan relief so he is liberal. Both are true and obviously those ideologies are not theirs, but these anomalies exist in an ocean of policy decisions they adhere to, the ocean which defines their actual bias. Look at the forest of policy decisions here, not the individual trees.
On the left side of things some (not many but some) there's a lot of apologizing for and minimizing of the horrific human rights records of the U.S.S.R. and China, some degree of falling for present day pro-Russia misinformation, and uncomfortable truths about the party's own closing ranks around people with a history of sexual abuse. And on the right there's a lot of deep-in-the-bones denial of evolution, or historical revisionism about their ties to the "party of Lincoln", or who won the 2020 election, and it's expanding every day to include new topics like prediction of hurricane paths to provably wrong information about nutrition, and so on.
I would say it's so omnipresently pervasive in the present day that it's impossible to wave away and is increasingly fundamental to explaining and understanding polarization.