You're wrong. NLRB regulations only require companies to negotiate with exclusive bargaining representatives. You're technically correct that unions can forego being the exclusive representative, but then the union can't compel the company to the negotiating table.
The essence of your complaint here is that if we do not allow unions to continue coercing people, then unions will not be able to coerce people! Oh no! That is exactly the point, exactly. Unions do not need to have these coercive monopoly powers. They need to reinvent themselves as voluntary professional associations that provide things of value that members are willing to pay for, and that buyers of skilled labor are willing to pay for via competitive procurement because of the unmatched quality of work and level of skill, relative to the price, that the members of these professional associations are able to provide.
Some union shops bid competitively, and get a lot of work that way. How? Because they simply provide the highest level of work quality and skill available. They train up their members well, they cover all the bases, they bring in people highly competent to submit professional proposals for work, and they do the work the right way, and efficiently. They're the candidate best able to provide what the buyer wants. They don't need to be able to coerce the buyer into never-ending negotiations until a deal is reached. The buyer wants it and is willing to pay for it.
I call them thieves because they accept the services of their coworkers but refuse to pay for it.
If I'm a sandwich maker and I literally force-feed you my sandwich against your will, and you don't want to pay me for it, I don't get to accuse you of stealing from me. On the contrary, you would basically get to accuse me of assaulting you.
These "thieves" as you call them can't refuse the services. Individuals in bargaining units have zero power to decide for themselves to accept the services or not. Unions regarding them as criminals as a result of something intentionally kept outside of their control is inexcusable.
The better earlier analogy is the one of tax evasion.
No it isn't, there are unmistakable and essential differences between taxes levied by governments and fees paid to private organizations.
What recourse are you leaving unions to police such unethical behavior?
It is not workers who are being unethical, it is unions. What unions do is deeply unethical. Once union security clauses are illegal and exclusive representation is abolished, the unethical and coercive nature of how unions operate will vanish.
Your goal is not to protect the freedoms of workers.
Yes it is. My goal is to protect the freedoms of workers against the coercive power of unions.
Your goal to destroy the ability of unions to bargain. It's transparent.
My goal is to destroy the monopoly power of unions, forcing them to reinvent themselves as voluntary professional associations.
I don't personally condone violence, but I do recognize it as an aspect of human nature. We have legal systems in place in part to give people the means to address grievances without violence. Take that away, and you create an atmosphere where violence becomes inevitable.
This is merely a slightly toned down version of your fallacious
argumentum ad baculum. It reflects very negatively on unions and the sociopathic mentality that they breed.