So we have "right to work" and "at will."
State laws regarding "right to work" apply to unions and dues collection. Regardless of the gains unions have made for the employees, you don't have to pay dues. You have the right to work there without supporting the horrible union. In fact, your employer will explain to you relentlessly how much better off you are, with lower pay and less benefits and less job security. On the other hand, good luck at the employment office or HR demanding your "right to work."
Which leads to "at will." You don't have to be an indentured servant or a slave! You have the right to quit your job whenever you like. "At will" allows you to move on when it suits you, for whatever reason you have. I don't know which states still allow slavery...but there's a law for that!
But then we have the 'quid pro quo.' The employer can terminate your employment "just 'cause." Unions require the employer to explain why, to have a "just cause." Without the union, now the employer doesn't have to explain anything. For example, your employer, say Walmart, determines after 4 years of annual raises, it is more cost-effective to terminate your employment than give you another cost of living/merit adjustment. It is cheaper to replace the higher paid employee with a new, low-paid body and start the process over again. And Walmart tells you "just 'cause" we want to.
So, both these newly bequeathed rights granted to us citizens are really not for us at all, are they? All servants have to serve their masters, so conservative Republicans have to serve, too. They have to pay their dues, or be terminated just 'cause.