Yeah, it seems sort of discomfiting to hear a claim that 'experienced professionals will sniff at this and not learn a thing from it'. You're not supposed to learn anything from this - its there so that the standard is set, and professionals - experienced, or otherwise - can refer to the standard, and measure performance against it.

An 'experienced professional' doesn't treat every document like a Bible from which new enlightenment can be gained. Often you need such things as this manual in order to quiet the rabble and give the mob something else to argue about, instead of eating themselves - as often happens when standards are not set and expectations not set and met.