[p333347]

The connotation of the word 'union' is of a group of poor laborers, often working in harsh environment, coming together for fight against arbitrariness of their rich employers with regards to matters such as salary, job security, accident compensation etc. I think it is fair to assume that even the lowest paid programmer is still paid at least above the average national pay in (most) developed/developing countries. Even those programmers that sulk at not being paid "enough" know that they are actually quite well off compared to most others in their society. Any grievance is highly individualized and will be negotiated directly by that person, with their lawyer if necessary. So union doesn't seem necessary.

Further, programmers actively look to change jobs whereas typical people needing union look to holding on to their jobs till retirement as much as possible. A programmer could also go freelance and charge whatever he likes. Exploiting loopholes in the current job contract, programmers could even do consultation or host a revenue earning webapp as a side business. A union like setup seems to be a hindrance to such activities more than being useful.

Finally, most programmers are highly opinionated and always seem to disagree on everything, not just programming things. It would be a miracle for a thing like a programmer union to even exist. :P