"your car has a defective part, *is unreliable*, and needs to be brought in to have that part replaced.".

Precisely! NHTSA determined that these vehicles are unreliable in this specific case, and thus need fixing. Glad we're on the same page. :-)

(I know, you want to pretend that it only ever means "physical repair" in everyone's mind, but that's a pretty big projection on your part.)