From reading the Rules in the "general market place" it looks like selling workers or brood across US states is prohibited. I understand why the selling of queens across state lines is prohibited but, for the overwhelming majority of ant species the workers can't reproduce so why would that be prohibited? an accidental release of workers in the wild is very unlikely to have any major ecological impact.
Allowing the selling of workers and broods can help people that are trying to start a parasitic queen or people with kids that just want workers to see whether their children has the patience it takes to care for ants.