There's a large, fixed costs associated with hiring anyone and large potential liability and legal threats. Prospective employers are reluctant to pay those costs and put up with legal risks, so even if unemployment checks were withdrawn, many would still be unemployable. It just isn't worth it to hire marginally productive people.
They'd be employable without government burdens, though.
Jeff Sessions mentioned this in his last speech before recess that big business should be looking for less regulation instead of cheap labor.