I never assume the recruiter understands the objectives of a job. All they have to go on is a list of job requirements written as a wish list by the hiring manager, they are seldom technical, and are usually less competent than you average engineer, especially about technical matters.

Good technical recruiters are rare, and seldom work for big companies like Google, Facebook, Amazon, Cisco, (Yahoo), IBM, etc. Most of them read questions from a script, and then believe that the map is the territory.