In truth, what fell was not the number of unemployed people but the number of unemployed people who are actively looking for work.
But that's the definition of Unemployed, not just in the US, but the International standard.
The Labor Force are those actually participating in the Labor Market It doesn't make sense to include those not trying to work, such as full time students, retirees, stay at home spouses, etc, and for those who claim they want to work but aren't trying to get a job, on a practical level there's no real difference between them and those who don't want work...none of them are trying and so have no impact on the labor market.
The BLS counts short-term discouraged workers (less than one year) in its U.6 measure of unemployment. That unemployment rate is 16.7%.
This is misleading. BLS also counts Discouraged workers (defined as willing and able to work, looked for work in last 12 months but not last 4 weeks because they don't believe they'll find work) in the U-4 and U-5. The U-4 is Unemployed plus discouraged as a percentage of the Labor Force plus discouraged. That's what the article implies the U-6 is, but the U-4 is at 10.2 %. The U-5 adds in all Marginally Attached: willing and able to work, looked for work in last 12 months but not last 4 weeks for any reason at all (mostly personal issues, not labor market). That rate is 10.9%.
What the U-6 actually measures is Unemployed plus all Marginally attached (NOT just discouraged) AND all people working part time for economic reasons. So that rate includes 6 million people who have jobs (just not as many hours as they want). It's dishonest to imply that the U-6 just includes Discouraged.