At risk of running against the obvious tide here, if you take the word "skilled" literally then of course everyone becomes skilled in whatever job they do. However, here "skilled" is used not literally, but in the sense of the industry term that means the job generally requires formal training and/or qualification before employment.

Edit: Not to say I don't think it's not a demeaning term (possibly intentionally so). It's a sucky word but let's not allow ourselves to become overly indignant by misconstrueing the sense of the term used.