The main issue with the UK's approach is approximately 10% of young people need acute medical care (e.g., ventilator access). There aren't enough hospital beds in the NHS system to meet that demand.
France reports that half their patients in critical care are under 60, which is supposed to be the "low risk" group.
In the Netherlands there are between 40-50 covid-19 patients in ICU in critical condition. Over half of them are younger than 50. (Youngest is 16yo)
Mortality is much higher for the older group, but hospitalisation happens a lot in the younger age group as well. Obesity is a high-risk factor.
A comment in the reddit post[2] which discusses that article notes that in China the 15-49 age group made up 41% of severe/critical cases.
(The below 50 age group accounts for a bigger part of the population to be sure. I see no data for hospital admission rate as fraction of the age group.)
[1] http://www.ad.nl/dossier-coronavirus/40-a-50-nederlandse-cor...
[2] https://old.reddit.com/r/Coronavirus/comments/fj1owh/over_ha...
There are no facts anymore, because nothing and nobody can be trusted.