The way I would do it is simply: no matter what, the employees get to vote down things their managers do. They can vote to do nothing, have no organizing body, and pay no dues, but they still get to vote, so if they want to prevent their bosses from doing something exploitative to them, they get to.
This model does not put you in a group anymore than being an American citizen puts you in a group by giving you the right to vote on things. In my version it is like how you get to be in a political party if you want to and not be in one if you don't, but you get to vote either way. The right to have some say against your manager's power in your life (short of quitting, that is) should be unassailable.
The fact that quitting is "all or nothing", and often not an option to people because the cost of finding a new job is high and often prohibitive to specifically the people who are most disenfranchised, makes it a poor and almost useless way to exercise power. Unions allow, in principal, for there to be intermediate pressures between "quitting" and "asking nicely".
Because it benefits the public good, the same way you're forced to be part of any country, state, city you reside in.
Also freedom of association is very clearly intended as freedom to associate, not freedom not to associate, so it's a little confusing for you to refer to it.
I believe you are arguing I could always choose not to work. I wish to work for an employer and the employer wishes to work with me. In this hypothetical there is required membership with an unrelated party I do not wish to associate with.
If I wanted to go to a coffee shop and that shop wanted to serve me coffee but the mafia is standing outside saying I have to pay them before I can go in, they are in fact forcing me to pay or turn away.
This model does not put you in a group anymore than being an American citizen puts you in a group by giving you the right to vote on things. In my version it is like how you get to be in a political party if you want to and not be in one if you don't, but you get to vote either way. The right to have some say against your manager's power in your life (short of quitting, that is) should be unassailable.
The fact that quitting is "all or nothing", and often not an option to people because the cost of finding a new job is high and often prohibitive to specifically the people who are most disenfranchised, makes it a poor and almost useless way to exercise power. Unions allow, in principal, for there to be intermediate pressures between "quitting" and "asking nicely".