The “just find a different job” position is the trivial case that doesn’t really add much to the discussion
Union security clauses cut both ways; they also require employees to join said union as long as the contract is active. You can't perform the job and be non-union.
"If you don't like the job, don't take it." It's like the argument when discussing child welfare policy where one side says "Don't ask society to help; if you need help, don't have kids". Or in healthcare policy, "Don't want high medical bills? Buy better insurance." While true, it is just a way to elevate above the actual problem without providing a satisfactory policy solution.
I guess I don't see why an employer requiring you to join a union upon joining the job is
a. a mandate (it's not) b. at all different from any number of things that an employer can require you to sign off on to start working at a job.
Union membership is "mandated" in the same way that when you accept a job that requires a 40 hrs/week, you are "mandated" to go to work.
> the actual problem
What is the actual problem? I don't see union security clauses as a problem, it's basically the only way collective bargaining can solve the free-rider problem and generally benefits the worker.
The problem is many people don't feel they should be forced to pay into an organization that doesn't reflect their values in order to have a job. In some ways, it's similar to the notion that many people don't feel they should pay taxes that go to support something they don't personally support (e.g., abortion, war de jour).
Right-to-work is a way around that in many peoples eyes. In my opinion, it's a policy that takes advantage of people's short-term bias.
Saying "just don't take that job" is like saying "just don't live in that society". It's not wrong; it's just not particularly helpful
I'm unsure of the relevance to "freedom of association" as a negative concept, though. You are still free to associate with who you wish, just as corporations are free to not associate with you if you do not join a union.
If we are going to transform a negative right to not join a union into a positive one, there are many other things I'd like to turn into positive rights first.
I don't think it is negative as a concept. I agree that, in theory, it is best to always err on the side of more freedom, not less. In practice, however, it can become negative if you think people don't always act rationally. Which is why I don't know if the right to work is good policy; part of me feels like it takes advantage of humans short-term bias, and leads them to limit their own long-term rational best interests.
It's very much like the social media debate going on right now. Part of me just wants to say it's better to have a completely open marketplace and let the chips fall where they may. But another part of me feels like there is a very real danger this will hijack human psychological shortcomings in a way that is not good long term. Maybe the cliché that "people get the government they deserve" is the closest I can get to reconciling the two.