I think the idea is that they don't see the bias. And while hurting Germany's export business isn't a problem (from the pov of self-interest), you can imagine

I think the idea is that they don't see the bias. And while hurting Germany's export business isn't a problem (from the pov of self-interest), you can imagine other situations where it would be a problem. To stick with example, say they really do believe these dangerous cars should be banned on American streets (and doing so really would save lives), but when they find out the car is their beloved Ford Explorer, they rationalize their caution away. Now the self-interest is getting them to make dangerous decisions, and they don't even realize that's what's happening.