I feel kind of uncomfortable going to counseling

[Rev. Rye]

I expressed my anger towards one of my parents mistakes multiple times. My anger has become serious, so I made an appointment for counseling. The problem is, I don't feel comfortable talking about this particular subject to my therapist. 
My parents' mistake has to do with religion, but I don't want counseling for my disagreement with religion. Yeah, religion makes me sometimes angry, but not to the point where I have problems controlling myself. I also don't fear being judged for my atheism on a regular basis. I don't know if my therapist is religious or not, and as much as I complained about religious in the past - including moderates - I won't mind my counselor being religious. All that I want from him is that he does his job right. I don't want to discuss with my therapist whenever religion is good or bad or how to live as an atheist, I just want to discuss with him about the fact that I was brainwashed by fundamentalists for almost a decade right under my parents noses, and when they found out they didn't understand how bad the situation was.
Here in Europe people are usually more indifferent towards other religions and atheism and most christians are moderates. But part of me still fears that my therapist might want to convince me to return to my religion. 
Also, I never talked directly to someone about my parents' mistake. The most I did was writing on this forum where nobody knows my real name. I know that the counselor will keep my secret and I met him before, I highly doubt that he'll judge me, but I still feel very uncomfortable talking to him about this.
What should I do?

At least in America, doctor-patient confidentiality also applies to therapists and counselors. I'm fairly certain things should be the same in Germany Romania. And going from my own experience with my therapist, if a counselor is actually doing their job right, they'll do what they can to help you heal; hell, she not only helped me heal, she also helped some other woman heal from psychological wounds inflicted in the same Lutheran school I got mine in. They're probably not likely to be looking for debate like the theists on this board. We do discuss religion and its excesses from time to time, but they're like Lt. Scheisskopf's wife said in Catch-22. In her words: “I don’t [believe in God]... But the God I don’t believe in is a good God, a just God, a merciful God. He’s not the mean and stupid God you make Him out to be.” (The exchange happens in Chapter 18, by the way; I'm Yossarian in this conversation.)

And I was going to say something about how religion is even less likely to be an issue in Germany (Especially if you lived in the former East Germany), but then I actually looked at your profile and found out that you were actually in Romania, the one Warsaw Pact state that actually actively used the pre-existing religion to further its agenda. That might complicate things a bit. Still, if a therapist is doing their job right, they won't try to convert you.