Just in case anyone is interested, you can find information about the history of labor in the US here:
http://www.aflcio.org/trivia/links.htm
And,in my opinion, arguing that one injustice should be ignored because of others is just not a solid arguement. Why bother doing anything then? Why bother trying to stop torture by one government when there are other governments doing it? Why try to stop rape when there are people being murdered? One does not cancel out the other.
Anyway, the site is a link of other sites with Labor hitory information. Very interesting. Anyone curious, go check it out.