What I suspect is actually not "helping", but rather "blind trust" -- e.g. just having an arrangement with the US where the US sends in "selectors" and the Germans send over the data; and nobody competent/willing to screen the selectors the US sends in ahead of deploying them.

I think there are strong incentives to turn a semi-blind eye to what the US is sending in (or what is going out) -- until shit hits the fan...