Some people just can't see that there is a difference between "system that has done some bad stuff at various but one the long arc of history learned and became the good guys" and "the ideology that never produced anything but an authoritarian murder furnace in every place it was ever tried."
I'm not condoning either side..
the road to hell is always paved with good intentions.
American style democracy hasn't planned out well in a lot of places.
but good guys? Both have enough big glass houses with oddly shaped panes of glass and rocks to throw,
and both are mirrors of each other but yet so much the same.
Might the soviet union have turned out different if it was less threatened at birth? Compare the times and one would say maybe, and then again maybe not.
The west supported so many shaddy characters and still does. SO did the East.
The east had a very public police state and human rights most assuredly sucked for many, but human rights in the USA up until the mid 1970's and into the 80's also were not for everyone in reality.
now lets talk the birtish, the French and other colonial powers and their treatment of peoples.
basically it boils down to nationalistic pride, money, influence and dick waving with neither side caring about ordinary people unless forced to confront the issues at the last second.
Granted the west talks a great game, and in some ways has matured quicker.
A big reason for somethings is that the east has usually been oppressed, its considered a baseline norm.
You went from the czar and the okrana to the soviets and NKVD to the collapse and the wild wild west of the 1990's.
The same would apply for many other states in the area: constant wars, oppression by neighbors, mass population shifts dictated by others, mass deporation and killings by who ever has the power at the time.
The USA on the other hand was an apartheid state for most of its existence, but has been relatively stable, Just happens that the government has been the biggest impediment to human rights.
Example: Civil war; hey lets fight this war to free the slaves, and then treat them second class for another 100+ years.
No one has invaded the USA since 1812 besides a few islands in the Aleutians.
We have been a collection of states that are federalized. Europe has been a collection of Nations that 1. distrust each other, 2, Monarchies for the most part, 3. eye each others resources, land and peoples and 4 relatively xenophobic ..
Hate breeds Hate.
If the west after 1990 work more closely with the Russians to ease the transition things could have been different maybe, there are lots of reasons why things are what they are.
There is no excuse for Stalin, Gulags, mass murder.
There is also no excuse for the western racism, colonialism, mass murders and other vile things that each side has committed in the name of freedom and money.
So, how to prevent the east / west divide? after 1812, keep the Russians closer to the west, avoid the east / west European divide and 2 world wars. ( biggest issue here, the west during this time frame was no better or worse. It's not like the west just woke up one day and said, oh wow, we have been real Jerks to the world.)
If the idea is in the 20th century: Options are as follows:
1. either go all in on the Russian Civil war. Pick a side and make a friend, this gives influence. instead it was half assed
2. Learn to work with Khrushchev and or Brezhnev and help the Soviet Union change. ( we helped China to some degree, yet they are not the role model of freedom )
3. set up a marshal plan for the soviet union or Russia in either 1945 ( make friends, gain influence )
or in 1991/2 same effect except you are influencing the post cold war and showing kindness and equality to those that you hope will be partners on the world stage.
Russia is and has been the key player in the East. Change Russia a little and you change a lot.
If you can make Russia more democratic and inclusive that goes along ways.
Start with Alexzander II - avoid the assassination, Like Austria-Hungary it will need to Federalize and democratize in the age of nationalism splitting very large states into parts.
Lots of variables here and lots of ways to make things happen, btu they will all take time and are not a magic wand.
It took a long time to end colonialism and Millions of deaths and countless suffering after.