Honestly, I don't think it's that. It's just that Western History is West-centric. In general that makes sense because an arbitrary human life has value approximately zero. For instance, 2 million people died in a famine in India under British rule but no one knows about that.

If it weren't for Hotel Rwanda, the Rwandan genocide might go unnoticed. The Khmer Rouge are barely known. And everyone might joke that "Haha the North Koreans have no food" on the edgier parts of the Internet but ultimately, 3.5 million could have died there and we would barely have noticed.

That's not even because of some evil ignorance - it's just that people always see things from their reference point (and not even big vs small). American Independence was a big deal to America but not a big deal to the UK. Brexit is a big deal to the UK but no one outside really gives that much of a damn. And think about the Vietnam War - it's this massive moment in American history but to the Vietnamese it is one massive moment sandwiched between their wars with two other superpowers.

The Rwandan genocide got a great deal of television coverage in North America at the time, nearly as much as the Yugoslavian wars. It was because the Rwandan conflict was so familiar to Westerners in the late 1990s and early millennium that a Hollywood studio was willing to fund a film about it.

Of course, now the tail might wag the dog, and the film might introduce the conflict to a younger generation that missed the reportage at the time.

There is a tremendous amount of denial and revisionism that goes on with all 20th century socialism, because the modern socialists really don’t want you to know about any of it.

its kind of weird to suggest that anti-socialist / anti-communist propaganda is somehow getting suppressed by some sort of socialist leftists. What an inane delusion to think socialists have that power, when in reality the west has a long tradition of making history fit their capitalist imperialist agenda by any means necessary.

No conspiracy is required. It works the same way holocaust denial does. Any individual person who support socialism is (via selection bias) incredibly likely to be a denier of the failures and humanitarian atrocities of 20th century socialism. If enough people espouse these revisionist opinions, you get to point where you can cast doubt over the facts of history amongst the general population. The only difference between holocaust deniers and socialist revisionists is that there's not enough people who hold holocaust denial views for them to be taken seriously by ordinary people. Depending on what polls you look at, about 40% of Americans think socialism is a good thing, and about half of the population would vote for a socialist president. So clearly your estimation of socialist influence is very understated.

Actually, modern socialists tend to be better at it then modern conservatives. Modern conservatives are too focused on trying to use it politically in contemporary politics.

The New York Times helped a lot with that too