Opinions are like buttholes; everyone has one, they usually stink, and are the source of all... unpleasantness.
People treat these "opinions" as legally binding when they are not. Like Executive Orders, they are only guidelines that apply to subordinate offices. Presidential Executive Orders are not laws. They apply only to Executive Branch government agencies, not to private corporations or citizens.
Attorney General opinions at the state and federal levels only tell subordinate offices how to interpret policy. Policies are not laws either.
Only Congress has the authority to make laws, and only the courts have the authority to interpret them. The courts cannot make laws either. The Executive Branch only has authority to enforce laws passed by Congress. When they step outside their authority, the courts rule the action as "unconstitutional" or "illegal".
It doesn't stop them from trying, though. The courts have ruled against the Trump Administration numerous times, and yet they continue because no one will arrest them and put them in jail, like they would if you or I were to pull the same stunts.