Reading my post again, I think to be fair we should say that Mexican unions can often definitely be corrupt in a way that doesn't serve the interests of workers. While this could result in people from there being very cynical about and uninterested in unions -- that is often my personal experience with people from former soviet countries -- my personal experience with people from Mexico (totally anecdotal and subjective sense, not proof in any sense) is still that they come from a culture where it's generally understood that collectively organizing as workers -- and collectively organizing for grassroots political power in other ways -- is a good thing, and a culture where they may have some experience doing so, very differently from most people in the USA.

It's just my theory based on my personal observations and thoughts though, yeah!