Initially they weren't. Then there was an obama era executive order that allowed work authorization for dependents of H1B, provided they have an approved green

Initially they weren't. Then there was an obama era executive order that allowed work authorization for dependents of H1B, provided they have an approved green card petition. Mostly only Indians use it because they have the biggest backlog in getting green cards. The current administration plans to revoke it so its going through its procedures.