Circuses, yes, archaically sometimes in the oil patch, but "unskilled" ???

Never!

When items of equipment can easily remove a finger, hand, arm or a life, and one must rely upon and trust the other crew members to work safely, there is definitely a considerable amount of "skill" required to do this job.

In our area*, the term used is/has been "Roughneck" ... for more than 50 years ... that suggests this nomenclature is more than a mere passing colloquialism.

*One of the top five oil-producing states in the US of A.