How do you define piss poor? The stats show that the US minimum standards still reduce fatal injury risks substantially. And your comparison point for 'rest of the world' is a German automobile club, not a government regulation. Would the better comparison be to ECE R129 for the EU?
> something about how they only test one head-on crash at 35mph and then extrapolate all the data from there
You know that the information is readily available and you could avoid spreading misinformation with a 10 second search, right?
The US regulation, FMVSS 213/213A, does a frontal crash at 30 mph as well as a side crash test at 30 mph. For apples-to-apples comparison, the EU regulation does a 31 mph frontal crash test and a 19 mph side test. All of the governmental tests are done on a standardized test bench. The German auto club test is 40 mph frontal and 31 mph side, done in a regular car.
There are also organizations in the US that do testing and ranking beyond the regulatory minimums.