Reminds me Life is Elsewhere where the main character is one of those "pure poet" types who doesn't have a problem informing on his friends and colleagues because he's just a poet, after all. Kundera does say that the art of writing a novel involves taking paths you didn't take in real life and exploring them. Of course, that's what makes his books so interesting is the way he mixes the autobiography and the storytelling.
Of course, according to the article, he was a member of the Communist party at the time. He didn't leave it until later. I hate the "Oh here's the totality of the man's artistic output" school of thought, but it does sound like his literary career is an attempt to atone for his early enthusiasm for the Communists that he would come to hate.
But then again, maybe that's just my own insight into the ways that the only schools of thought that I find myself hating are the ones that I once loved wholeheartedly and only later saw the cracks. Of course, that's not always true. Some things I realized were utterly idiotic (like when I was 9 and really liked those record burnings as a way of ridding popular culture of Satan) and other things I have gone through phases in my attitudes - love, hatred, and ultimately an "eh, not for everyone" attitude (Christianity, Communism, etc.) So maybe it was good that I took 10 years to convert to Judaism. I could go through all the permutations (infatuation, dissatisfaction, lingering affection, loving some aspects and hating others,etc.) before I knew that it was for me.
Ok, so I took an entry about Kundera and turned it to me. Then again Kundera tends to take books about fictional characters and turn them into discussions of his own head games. Sometimes they work (Slowness, Unbearable Lightness of Being) and sometimes not so much (that book I mentioned above or whatever it was name)