ETA: The only time I ever have a problems with unions is when they're mandatory. When you must be part of a union in order to work at that job, and no alternative exists. I don't really see that as a whole lot better, because it causes many of the same problems with dynamics that occur when there's no union and a large employer exerting undue power over the employees. It's just the other way round - a single large provider of labor exerting undue influence over the set of employers. As long as they're voluntary I'm all for it. Of course, that does assume that employers aren't engaging in shifty sneaky dastardly tactics ala Walmart. Not always a good assumption, that.
I can see the purpose, in some cases, to force employees into a union if they want to work a specific job in a specific industry in a specific company. Especially in these so-called "right to work" states, of which the state of PA, where I reside, is one.
Thanks. That little icon thingy it gave me scared me for a moment when I first saw it.