The term would indeed embrace most of the adult male populace, if simply taken at face value. Right up to the chief exec and politician types earning being paid prodigious sums to do a very questionable amount of 'work'.

As used in song and verse the term is generally a shorthand for the (predominantly manual) labouring, probably lower-paid, masses. The shorthand is imprecise, but necessary, as a full description of the employment circumstances of the working man would otherwise overwhelm the purpose of the composition, besides being a bugger to put into verse.