As a former member of a union, I honestly find it odd at how many people think that unions are always good. Of the two unions I was a part of and watching what my dad went through with his Union I'm actually fairly anti-union at this point in my life. I watched a guy get fired for sexual harassment, and rehired due to pressure from the Union. I watched my father not get a manager position, because of seniority ruling…
One is that there's a great deal at stake and most companies are going to resist unions any way that can, and we can reasonably expect that to include negative propaganda.
A second is that unions really are terrible because corporate interests have succeeded in subverting the unions they couldn't destroy and have influenced them in ways that render them dysfunctional in hopes that that will discourage employees from joining.
A third is that unions have an inherent tendency to become terrible due to internal dynamics.
I suspect all three of these are true to some degree. It seems like a good way to defend against the second and third is to have multiple competing unions and allow employees to move freely from one to the other, or start up a new union if none of the ones that exist are any good.
Like most HN readers, I don't have any experience working in a unionized industry or know much about how rules governing unions vary from state to state or which unions are better than others or what kind of checks and balances exist internally to prevent unions from become corrupt or ineffectual.
I do expect that if the tech industry were to become unionized, we would need a different kind of union. It makes sense for unions to force people to work slowly in industries where employees are at risk of ruining their joints and then being discarded by the company when they can no longer shovel their daily quota of coal. In software development, anything that slows you down is frustrating and I think most of us would rather work in an environment where under-performing employees can be fired than one where they can't. We could borrow plenty of ideas from existing successful unions, though.