Either they are just dumb and designed Dual_EC_DRBG by accident, or they design systems like that for a purpose. Your assessment of what they need is an assertion, based on what exactly? Security is designed not around what one thinks an attacker needs, or why they would want do do something. It's about preventing an attacker from getting access to things a person wishes to keep secure regardless of why they would want to. In that light weaknesses in random number generators is a relevant field of inquiry. Otherwise simply ignore cryptography altogether, trow up your ands and say why bother.