I can only partly agree with this. Many Germans, probably most, don't agree with circumcision, but it's certainly not unknown and not limited to the muslim population. I've seen plenty of white 'German" German guys who've been circumcised and although I didn't always try and look too closely, I'd say most of them were infant circumcisions.
To add to this, and I think this is more relevant, the numbers of young women I've heard directly (ie - I've had conversations with) or overheard in passing, who are familiar with and have had experience with circumcised partners, continues to surprise me here. It's considerably higher than I ever thought it would be.
So, while I agree with you that probably most Germans would not think about circumcising their son immediately post birth, it's definitely not as unknown or as 'foreign' here as many people might think.