I didn't really think about Mayday until the homily at mass. Apparently, in 1955, we started celebrating work on this day, right along with the commies. When I hear stuff like this, I get a little upset, and I start wondering if the Orthodox have to put up with stuff like this, but the priest redeemed the situation a bit. He explained, for instance that the gospel with Jesus refered to as the son of a carpenter (and one can infer Jesus worked with Joseph) combatted the heresy of Christ being only divine in nature. In other words, Jesus as a worker, which likely did happen, counteracts the false image of Jesus as superman.
I don't think work equalled identity until the industrial revolution was well under way. There's alot that's not pretty about industrialization, but it seems to be a necessary stage. In any case, it's far better than subsistence farming, for example.
As anyone can see, by, for example, watching Globalisation is Good, industrialization is but one stage. The sons of factory workers become knowledge workers, in general.
But biblical references to identity via work are few. Indeed, the carpenter is Joseph; it's merely presumed that Jesus worked with him. For Jesus, words like Messiah, Son of Man, Son of God, Son of David, etc... were far more important identifiers. Even during industrialization, the workers never came up with this stuff. Marx, who was pretty far removed from the experience of the workers, did.
Work as identity, as a concept, is astonishingly rigid. It, like the body of socialist thought, doesn't really allow for children or old people, the poor, etc... If you can't work, you don't have an identity- perhaps stating the it negatively illustrates the point more effectively. I know the false charity of "each according to his needs" can throw people off, but one must remember the person in power determining who needs what always decides that he and his friends need more and other people (especially those with no identity) need less.