I'm not from the US, and neither are the people we're talking about. These people look like they weigh less than 88 kilograms, which I agree would be obese for 176cm.
Oh I wasn't aware that there were testable definitions. Then I consider it unlikely that the adults in the German family are either obese or overweight. On what are you basing your claim that their BMI is greater than 25 kgm^-2?
Also BMI is getting phased out in favour of ratio between circumferences of hips and belly. It has much better correlation with lots of diseases than BMI.
Are you obese (by your own standards)?