imo, there is an “apolitical” way to begin to break it down, but it won’t work in isolation.

First, listen to what they have heard/believe, and then simply lay the seeds of doubt by treating them like an adult, critical-thinker. Start from a position of agnosticism about historical judgement, but inquire about the inconsistencies that occurred over time that seemed overtly dishonest, “I have heard those things too. But, I think history is written by the winners, and I am skeptical of some of the things I hear people say about cold-war history, because it hardly ever stands up to any scrutiny.”

here is a practical “apolitical” example:

The dichotomy between US war-time media (propaganda) and cold was propaganda. A great source for this are political cartoons. During the WW2, the US media portrayed Stalin as a wise fatherly type figure and friend of the people. “Uncle Joe” There are so many examples. Emphasize that those aren’t necessarily true, because we know, as grown-up adults that can think for oneself, that Stalin was simply a human being, not a larger than life figure. That they intentionally crafted an image of him to suite war-time needs. But, the same could be said for the post-war/cold-war media, where Stalin was painted as a maniac. Look to political cartoons during the early 1950s, particularly the american war in Korea, where Stalin is portrayed in a starkly different manner, an overtly racist caricature of a fur-covered animal/brute, hell bent on world domination. But, even in that time, with that hatred, people would acknowledge that Stalin and the Red Army were on the right side of the war and Soviet casualties were not only grievous, but Nazi Germany was culpable. So why is it people can’t even stand to admit that today? Things have become even more exaggerated.

This points out a definite contradiction, one simultaneously knows that at some point the US media was willing to portray things as they are not. But perhaps the truth is that they are always portraying history and people for a particular purpose- never truly as things are, so the truth should be sought after as the picture is likely more grey, or complicated, than what you hear people say thoughtlessly. Ask them, do they think the US/western media is honest? Were they honest about Iraq1/Iraq2/Vietnam/Iran-Contra why is this different? Do they think popular history about, say, the founding fathers is truly accurate? Is Hamilton real or a broadway show? When someone makes a claim about history, how often do you think that person has truly tried to studied that history deeply? Usually it isn’t too deep, they are just repeating something someone told them as an unquestioned fact, backed up by the fact that “everyone knows it.” This extends to popular history, too. Uncomfortable truths, like, “George Washington was the wealthiest man in North America, massacred indigenous people to provoke a war with the French for land, and owned Slaves since he was a child, and started a War of Independence to maintain his wealth and status.” upset people and generate pushback without any real academic dispute, but people still write, and sell many books about how awesome George Washington was while glossing over the truth.

Then hit them with another dose of reality: history is written by the winners. Stalin was succeeded by someone who solidified his legitimacy by dumping on Stalin’s legacy: i.e. Khrushchev used mistakes or “crimes” made during Stalin’s time to silence his political rivals and shore up his rule, is the same way nearly any opportunistic political figure has in history. So even internally, for decades Stalin had few defenders after his death. Now the Soviet Union is gone. So for decades, internally and externally, everyone in power has had a vested interest in painting Stalin as a monster. The only people writing critical perspectives on that history, outside of a few academics who are treated as unserious or fringe, are academics who want to be taken “seriously” by publishers or western academics. Stalin has been so caricatured that if one were to work to “revise” the “common wisdom,” they lose access to a large audiences and tarnish their credibility with absolutely no upside. So many historians simply work on less contentious topics and defer to the work of “respected” works, as the media, and other academics will simply dismiss their work. New York Times would cover a book exposing another “secret atrocity” of a US political enemy, but they aren’t going to publish an article on a book that scrutinizes conventional wisdom on this topic because their editors will ask, to what end are we covering this crank? But nonetheless, the history is there… Have they read it?