I thought right-to-work is an antiunion mechanism?
The idea used to sell it is that you don't owe your employer any loyalty, and they don't owe you any loyalty; either of you can walk away at any time.
In reality, this creates a completely asymmetric power dynamic. You can be fired at any time, for any reason, which means you have little power to advocate for better compensation, safer working conditions, and so on.
What you are describing is "at will" employment.
Right to work means that you have a right to choose whether or not to be in a union. It effectively makes "union shops" illegal.
Unions don't like it because it makes them less effective.
Where your comment misses the mark is that workers in non-rtw states don't have to join or even pay for unions. They can work for companies that do not have union security agreements. There is no coercion in any step in the chain.
right-to-work laws simply say that you can work for a company without being forced to join the union that is representing some/all of your fellow workers. Forcing workers to join unions (and pay dues) in order to get a job greatly enhances the power of union bosses, and as we all know, power corrupts.
It's not that simple. Right-to-work laws say that even if you don't join the union, you can't be left out of the benefits that the union negotiates with the boss. "Right-to-benefit-from-the-union-without-paying-dues" doesn't sound as fair as "right-to-work" though.