1. Generally refers to uneducated laborers who work menial factory jobs for a set wage. Also refers to union workers who generally give up all aspects of personal accountability for the security of union tenure.
2. Blue collar is now synonymous with union drone. He will do what the union tells him to do, when they tell him to do it. This is especially true during election time when the union endorses one candidate over another. The endorsed candidate will get the lot of union votes, usually for favors paid to union leadership after the election ends.
3. Blue collar is synonymous with the decline of American industries and the creation of the "Rust Belt". Blue collar workers got greedy and demanded unusually high wages and benefits for a decreasing amount of work and responsibility. This resulted in many unskilled labor positions being moved to other countries. See steel industry and automotive industries as example.
See that guy, he is one lazy ass blue collar man.