Likewise, many recruiters are unwilling to work with candidates who are currently unemployed.
Unemployed candidates look less desirable to the clients.
They are also likely to send their resumes to other recruiters and directly to potential employees. They prefer to place currently employed candidates who leave one job to take on another. Most likely, it's a blind call. You may love your job today and have no interest in making a change, but your situation may change radically tomorrow. The recruiter you hang up on today may have the job of your dreams tomorrow but may prefer to work with a more congenial candidate.