"Working class" is a term that has many and varied meanings, especially over time.
The German working class of 1807 has essentially nothing at all to do with what most of us probably think of as the working class, the blue collar American workers of most of the 20th century. That working class has largely disappeared along with the jobs they did.
Today, the "working class" is often just used, especially by liberals, to mean "the poor," and it is a class that on average does remarkably little work.