Regardless of how any employer decides to fill a position, the position is filled. Even if they hire the CEO's paramour, it is one more person who was (presumably) without work and now is gainfully employed. So it's a Plus-One for the economy.
From an overall societal standpoint, it doesn't matter how the choice is made.
If an employer has a policy that they won't hire someone who is currently unemployed, the ripple effect remains. The person who is hired by company A leaves his position in company B, thus creating a vacancy there. They have to fill it.
Current employment status is a legitimate consideration for any employer to notice. One can only hope that they are rational and accept the possibility (likelihood) that the person is unemployed through no fault, but rather due to factors outside her control. But even if the employer is stupid or close-minded, how the position is filled is irrelevant, statistically speaking.
I lost my job four times over the years due to cutbacks, reorganizations, and so on, and NOT ONCE did an employer indicate to me that there was a concern about my being unemployed when they hired me. In fact, they were happy that my negotiating position was compromised, and they could get away with paying me at the bottom of the scale.