Spot on. The fringes are so blinded by zeal they're unable to recognize these glaring parallels.
Conservatives and centrists are so zealous in their attempts to make it seem as if the alleged
"glaring parallels" between Hitler and Stalin are something that they don't have in common with politicians in democracies:
Both preferred to solve political problems by resorting to violence.
What is the point of issuing weapons to the armed (!) forces and the police in democracies?
Both had a driving force in the form of a Party organization.
Don't democratic politicians have party organizations?!
Both had a strong, authoritarian leader at the top (Hitler v Stalin).
Are leaders of democracies weak and anti-authoritarian? Is that what they are lauded for in speeches?
Both had a secret police. (Gestapo v NKGB/NKVD).
Are the secret services in democracies not secret?
Both had the head of the secret police as the second most powerful man after Dear Leader (Goebbels v Malenkov).
Wasn't J. Edgar Hoover pretty powerful? Aren't the current leaders of the FBI or the CIA powerful? Why do we even know the names of guys like Christopher Wray or William Burns?
Both had an official youth organization (Hitler Jugend v Pioneers).
Are there no such youth organizations in democracies?
Both built Empires.
Don't democratic states?
Both installed puppet government leaders in the conquered lands (Quisling, Ryti , Reihl, Petain v Pavelich, Ulbricht, Rakosi).
Didn't and don't the UK and the USA install puppet leaders in other countries? Ever heard of Reza Pahlavi? Pinochet? Or, more recently, Jeanine Áñez?
Both had an organization offering free holidays for deserving workers and their families.
Sounds good. What is wrong with free holidays for workers? Should holidays be exclusively for the propertied classes?
Both had rallies and parades (Nuremberg v May Day).
Are there no rallies and parades in democracies? Really?!
Both had their "bibles", (Mein Kampf v The Brief History of the Communist Party).
Are there no "bibles" in democracies?
Both had a penchant for burning books they disliked.
Aren't books burned in democracies? Book burnings seem to have become very popular recently.
Both had an elaborate set of camps to which undesirables were sent (Concentration Camps and Death Camps v "The Gulag Archipelago".
Aren't undesirables in democracies imprisoned? In skyrocketing numbers!) Are there no current plans to send homeless people to camps?
Both adopted mass starvation as official policy.
Is there no more hunger in the world ruled by democratic countries? And in those countries themselves?
Both had their martyrs.
Do democracies have no martyrs?
Both had a total disregard for truth.
Is truth valued in democracies? (I mean, other than in grandiloquent speeches!) Aren't posttruth, truthiness, and alternative facts in high regard in democracies?
Both had a vast and elaborate range of informers.
Don't democracies have those?
Both demanded that children denounce their parents if they deviated from the true and narrow path.
Are children in democracies discouraged from denouncing insurrectionist parents or other family members?
Both signed treaties they never considered to be bound by.
Do democracies never break treaties? (And if they are powerful enough, don't they simply refuse to be a part of treaties to save the world?)
Both had an arch-enemy (Jews v Capitalists).
Don't democracies have arch-enemies?
And finally, the addition to the list:
Both were led by a little man with a silly moustache.
Are democratic leaders never short men with silly mustaches? 
(Hitler's height was actually above average.)
My post about this list with links was removed to AAH, but my point is (and so was shemp's, I imagine) that arbitrary things Stalin and Hitler might have in common is a weird way to prove the alleged truth of a
colorful circle as an illustration of an alleged political principle. There is nothing
glaring about it other than the colors themselves.
I can see why some people desire to see Stalin and Hitler as diametrically opposed to secular liberalism, but painting them at the opposite end of a scale or a circle really doesn't do anything other than illustrate people's favorite
fantasy of what constitutes
secular liberalism. The irony is that communism (and as mentioned in the removed post: Few people killed as many communists as Stalin, probably not even Hitler) and National Socialism are so conspicuously
different that not even 'the politically closed loop' manages to unite them. Instead, they are supposed to be united as (or lead to?) anarchism and subservism to 'illustrate' that
"the journey between Left and Right is a very short one."
In other words, we have seen no real argument for this idea or any fact to support it other than the
zeal of some people to have their fantasy illustrated in this way.
And don't think that I am unaware that Nazi death camps were different from the U.S. penal system and served a different purpose, or that children's denunciation of their parents in Nazi Germany -
Spying on Family and Friends (Facing History) - wasn't different from a son denouncing his insurrectionist father to the FBI:
A son explains why he turned in his father over the Jan. 6 attack (NPR).
But it still seems to make a hell of a difference to some people whether violence is used in the service of 'our' system or in the service of the systems we despise. People tend to think that nationalism is great - as long as it's not the nationalism of our enemies. That's when it becomes apparent to everybody that nationalism is bad because
their nationalism isn't
our nationalism.
Our nationalism is
patriotic! And true patriots ignore the atrocities of their homelands and focus on the atrocities their enemies.
When do false flag attacks become despicable? When our
enemies are the attackers. When
our country is the attacker, false flag attacks are clever tactics meant to confuse the enemy.