My personal view .... hope i did not misunderstood the writer but my point is dont just look on surface of any report .
Defined by wikipedia ..... "
Unemployment is the state in which a worker wants, but is unable, to work. The unemployment rate is the number of unemployed workers divided by the total civilian labor force. The unemployment rate is also used in economic studies and economic indexes such as the Conference Board's Index of Leading Indicators (US only)."
With that in mind, Point (1) is irrelevant. And correctly so if the person do not need a job or not in search for one because its not important to him/her then it has no economic impact to the country. Note why we use unemployment rate ? .... as an economic indices.
(2) The writer must be updated and recognise that time have changed and with technology etc, the terms and state of employment will change ... we must accept that part-timing, contract employment and home-based employment will be part of our lives and a norm in the future. Hence he should not refer them as "stealh unemployment". In any case, for economic indices purposes, you are either employed or not, whatever the terms are irrelevant.
Point (3) is even more ignorant. Similarly, with technology and changing times, working hours should not be used to calculate employment rate. I personally have short working hours but my productivity with respect to my business/sales objectives exceeds expectation. Hence, longer working hours does not mean Productivity (Productivity is an economic index).
Even if the unemployment rate is 20%, you still got to look into the demographics that make up the 20% to understand if it impacts the country's economy. For example, if majority are low skill workers, the impact to the country whose economy is driven by high value manufacturing may be minimum.
You may also have the case of a rich country where employment rate is high but only because the citizens are rich and do not need to be employed. So the rate is irrelevant to its economy,