(Edit: I know nothing about the Dvoracek case, having heard the name only just now.)
If by "emerging victorious" you mean forcefully taking power with a Coup, ready to perpetrate their own horrors to stay in power at all cost, then we agree..
Also considering that the communists were backed by the Soviets, with decades of mass-purges of their own, it possibly didn't take much imagination to understand the type of regime being supported.
> I imagine many young Czeck people would have bought into this way of life
So much so that the communists need a coup to gain power.
On the other hand, Kundera was an intellectual. For some uneducated it could have been waved away as nescience, but not for him. The criminal nature of the regime was not hidden. It put people in labor camps (a sentence which was often deadly) just for being a clergyman, a hero WW2 pilot liberating Europe or just for having homestead. It banned writers and other artists. On the other hand, the judicial murder of Milada Horakova [1] which I believe might have opened eyes to many hasn't happened yet, trailing Dvoracek's arrest just by few months.
Like I am disgusted by some of the effects of modern unbridled capitalism but I would not support any movement that restricts the liberty of fellow humans in such way.