The lower unemployment is bad for the market because the only thing still keeping the dollar valuable is its artificial scarcity.
Why are banks raising criteria to get a loan? It’s complicated but here are some reasons. Inflation hurts their bottom lines because they are in the business of selling debt and inflation erodes the value of debt. Also people have much more saved up after the pandemic and they are getting jobs now and expecting higher wages. Therefore banks are scared of inflation setting in because the dollar is no longer as scarce as it was. And if they start handing out loans then the dollar becomes even less scarce.
Continuing- the lower unemployment numbers today mean more people are making money and therefore there is less scarcity of the dollar and more inflation. Hence market down on good news.