It's not like they have had weak socialist movements.
in Estonia the Bolsheviks got 40 percent of the vote during the 1917 elections. The Latvians had their famous riflemen.
In the 1920s there were active underground communist organisations in all three of the baltic states.
Now all of that is forgotten. They've managed to rewrite history so efficiently and without opposition. The new generation openly praises fascist despots like Ulmanis, Smetona and Päts.
The fascist despots of all three respective states were not exactly the most popular rulers. After all, why do you think their house of cards collapsed so easily in 1940?
Also, it was not like the communist were the only ones in opposition to them either -- many social democrats, liberals and members of the national bourgeois were in opposition to the rule of Päts in Estonia, Ulmanis in Latvia and Smetona in Lithuania (most likely due to the semi-colonial nature of their governance).
But now these unpopular dictatorships are revered in these nations. Monuments to these men built without opposition.
How?
I have a 90-year old neighbour from Estonia who immigrated here, after he retired. The way he describes it, the youth in the Baltics in the late 70s and throughout the 80s were for some reason attracted a lot to Western culture (films, rock music, jeans, etc). Because many of those things were inaccessible or banned, they started feeling resentment towards the state. Now those people grew up and are running the countries.