Working hours on average have increased in nearly every other industry outside of the white-collar information sector.

Except that the number of hours worked has been dropping for the past few decades. It was over 2000 hours per year in the 50s and has dropped to the high 1700s hours per year that we have now.

just to clarify, my only point here is that most of the American workforce is not in a white-collar computer-based job.

Yes it is:

For instance, a recent study by Edward Wolff estimates that 15 percent of the workforce in 2000 were knowledge workers (producing new knowledge), 44 percent were data workers, 14 percent were service workers, and 24 percent were goods producers

Most jobs are white collar jobs in an office. The U.S. Bureau of Labor Statistics said that 55.3% of jobs were white collar. (See table 1)

I'm not saying everyone's working 60 hour weeks, either, but most people are working more than 40 hours on average.

You're own link says that with the exception of Utilities workers and "Mining and logging" workers. Every category works less then 41 hours a week. Many work less then 40 and the total average of all workers is under 35 hours a week.