Wrong. Imagine the economy took a downturn and the company was having trouble finding placements for their consultants. Imagine that they decided to hang onto the employees even though they didn't have billable work for them (try hard: you may sprain your imagination). Imagine that the company's finances were in trouble over this, so they stopped the janitorial service. And then they asked you to take out the trash and clean the fridge.

THAT is when it would be appropriate, and a team player would pitch in. Abusing employees is abuse whether it's excessive billable hours or excessive fridge-cleaning.