The only thing I can come up with is the ridiculous number of civil wars, in America, Spain, Romania, Ethiopia, Russia, the AOG, National France and even Brazil and South-Africa (though then it are just a few partisan units trying to reach the capital).
I think it's two things. First off, unlike IOTL, WWII isn't (mostly) confined to Europe and East Asia. There's wars all over the globe, almost no country is safe.
Yes, this is a very important factor too. Even IF representative democracy endures in the event of the Syndicalist Internationale being defeated in WK2 by a relatively democratic Germany, the rise of Republican Russian/China, the Entente remnant retaking their homeland without going full authoritarian, the rise of a liberal Japan acting as 'Asian NATO', etc.... The world will still end up being significantly more right-wing compared to OTL.
With the exception of China and Japan, ALL of the potential torchbearers for democracy mentioned above had at lease one violent, bloody, nation wrecking military confrontation against the the forces of radical left-wing socialism.
Think denazification in Germany, and how the Nazi were perceived by the rest of the world even today. It's going to be drastically worse for any leftist in the Kaiserreich timeline for at least a couple of decades, maybe up until the the early 21st century (similar to how many extreme nationalist ideas are making a comeback in the form of the alt-right after more then 60 years since the end of WW2 in OTL).
No matter how much one might be a true believer in the ideals of democracy and the freedom of speech. One does not win a war against a bitterly ideologically opposed opponent and then allow said opponent to take power peacefully through the ballot-box, or even openly spread their 'ideological contaminant' in classrooms and newspapers afterwards.
If any capitalist faction won their war against the syndicalist, it would be highly implausible for them to allowed even moderate socialist parties and trade unions to continue to operate without any significant violent harassment against their members, voter intimidation, campaigns of deceitful propaganda by state, etc. Anything that is even remotely socialist is going to be political and social suicide to a degree far exceeding OTL.
For example, think the Civil Rights Movement in the US. In the event that Reed becomes president in the 1936 Election, he will be the only American faction that have the option to take on African Americans as government ministers. During the Second American Civil War, even if the CSA takes on Norman Thomas' social democratic ideas as their own and doesn't go full totalist, when the 'Private Bank Accounts' (In which the bank savings of wealthy individuals gets nationalized by the CSA government) and 'The Law of the Land' (in which leftist militia seize control of private properties belonging to religious organization and the rich and redistributing them) events get triggered , there is a 90% and 75% chance of the CSA saying 'Yes' to both of them.
Imagine a child from a white, upper middle class family say... living in New York. He will have vivid memories of his family's hard earned savings in the bank wiped out by the CSA overnight, followed by left-wing militias (most likely with quite a few members from the low-income African American communities) kicking them out of their apartment, if not outright shooting his father for being a 'class enemy'. Even if the US Federal government wins the civil war and restore democracy, you will still end up with an entire generation of society's upper crust becoming radicalized due to their terrible experiences during the CSA uprisings. When the 1950-60s come around and the ATL version of Martin Luther King Jr. emerges, will they jump into 'fight or flight' mode, and immediately associate any form of black empowerment with Reed and the CSA?
The only way that I see this being averted will be for the Second Russian Civil War to breakout, but have the Left SR-Mensheviks in power at the time fighting against the Bakunin's Bolsheviks, or for Nationalist France to reclaim at lease part of their homeland from the Communards while under a government led by the Republican-Socialist Party. This way, their will clear dissociate between Social Democracy and Syndicalism, with the former playing a key role in taking down the latter.