Labor organizing is a bad thing because laws as they stand allow unions to over-ride the contract liberty of companies. This gives them enormous power that lets them engage in rent-seeking behaviour. There is plenty of economic scholarship on the efficiency hit companies take from unionization, and plenty of anecdotal examples of major American industries crumbling after coming under the thumb of powerful unions.

You lost me at "labor organizing is a bad thing"...

There are some flaws in the labor laws in the US, and the first thing that comes to mind is the fact the "Union Monopoly", ie once a Union is established there's no competition. If you allowed for competitive union practices, then you no longer allow for rent seeking by that union because someone can always just organize a different, "better" union. I don't really care which happens first (union formations or reform to labor organization laws) but both would be my goal for a long term solution.

If contract liberty were guaranteed, unions would lose any utility they have to their members. Before labor laws were crafted, unions used their numerical advantage to intimidate companies and other workers into respecting their monopoly on a workforce. With labor laws, that monopoly is guaranteed by the law. Either way, unions only work with a force-backed monopoly. If a company can fire workers when they unionize or strike, they will.

A potentially viable free market alternative to unions is worker coops. They have the resource-pooling and sharing of unions, but without the coercion and rent-seeking.

You: Labor organizing is bad.

Also you: a free market alternative to <organized labor> is <organized labor>.

You hate the word union. You seem to have a problem with how unions function in the US. I agree! Having all carpenters represented by a single union isn't necessarily as good an answer as having all carpenters represented by several unions. It creates other problems (unions competing against each other leading to race to the bottom rating, mass firings, etc) but it's really no different than companies just hiring non-union laborers now and would hopefully lead to a larger percentage of labor represented by orgs and not individuals.

There absolutely should be laws in place preventing retaliation and allowing organizations, I just don't think the US model has done well.

I don't see any moral justification for violating someone's contact liberty. If someone does not want to employ unionized workers, or workers who go on strike, they should not be forced to. Freedom is a two-way road. You have a right to do whatever you want including organize and strike but you do not have a right to force other people employ while you do these things.

I simply cannot wrap my mind around the idea that it is morally permissible to restrict freedom-of-association/contract-liberty in this way.

The concepts of unions aren't changing. Unions as a whole are shrinking because the "power of all" has been found out to be bullshit. New sectors unionize and find out they make just as much money but are now shoe horned into group think and pay losing the ability to thrive as an individual which eventually just results in the lowering of quality, expectations and results. I don't know of a single good example of unionization in the tech sector or in fact any new sector in the last 20 years that has resulted in positive outcomes. I'd love to see an example if there is.

If everyone thinks they're the magical special worker who can command the top tier of their sector's pay scale, then no, unions don't work. However, that's statistically impossible. Most people are, by their nature, average. You might lower your ceiling in the union, but you also might raise your floor. This is of course assuming that a union is even involved in wage negotiations at all. It's also possible that you just have a trade organization that can exert pressure on the organization in other ways, and focus more on "quality of life" issues that most tech people are actually concerned about.

I'm still waiting for an example of a sector that has benefited from newly becoming union? So far as far as I can tell every example is nothing but a billboard for "DO NOT ENTER".

Dangerous manual labor roles, like those served by UMW and UFW, certainly benefited upon their organization decades ago, but labor law and enforcement is much stronger now.