Elijah Grajkowski is not being straight forward. He does not want the right to join or not join a union, he wants the right to be a parasite and not pay for the union.
Elijah knows very well that federal law requires unions to represent all employees, not some, not only those in a union, but all employees.
So, in a all practical senses he is in the union either way. What Elijah objects to is having to pay for the services he receives.
This would be akin to claiming that I don’t want to be a Wisconsin citizen and thus should not pay for using the roads every day. Elijah, of course, is not saying he would not use the roads, but he just does not want to be forced to pay to use them.
Someone complaining about being forced to pay to be in a union is like someone being forced to pay taxes to fund elections. Yes, both could be framed as one being forced to pay, but just as I pay city taxes for my right to vote in civil matters, likewise, I gladly pay my union dues for those same rights in the workplace.
Its what Democracy looks like.