The point that he's making is not that individual observation should trump objective measures, but the epistemic claim that if what we perceive contradicts those measures, it's worth interrogating the validity of those measures.
I don't think that the particular example that you're giving is "fraught with peril". Note the lack of an upper bound on the labor force participation rate that you cite - 16+ includes people of retirement age, whereas the measure given in the article shows that the official unemployment rate for men 25-55 is just 1/3 of the "true" unemployment rate that includes disaffected workers. This is significant.
I don't think that the particular example that you're giving is "fraught with peril". Note the lack of an upper bound on the labor force participation rate that you cite - 16+ includes people of retirement age, whereas the measure given in the article shows that the official unemployment rate for men 25-55 is just 1/3 of the "true" unemployment rate that includes disaffected workers. This is significant.