The precise form of organization can be grown organically to fit the situation, whether you call it a "union" or just as "association"
The point is that programmers should organize so that they can improve the pay and general standard of life of every programmer and so they can increase the quality and value of every programmers output and the esteem of the profession in general.
Programmers should treat their profession with the same seriousness that Doctors, Lawyers, Psychologists, Actuaries, etc treat their professions. They create professional bodies that stand up for their interests whether it is by lobbying, marketing, bargaining, etc.
How is it that calling something an association will avoid the problems from being a union in the US?
> The point is that programmers should organize so that they can improve the pay
It's poor form to assume your conclusion.
You keep bringing up doctors and lawyers (and you misstate what their professional organizations actually do and overstate their influence), yet your goals for a "programmers association" are more akin to those of teachers unions.
I understand why you want to avoid the comparison with teachers unions, but the only legitmate way to do so is to stop pushing the same thing.
Saying "this will be different" isn't enough. Same means, same ends.
Given that, would you recommend that programmers join unions in the US? If so, why?