Because they don’t have the majority.

Neither did Republicans when Tommy Tuberville was blocking all of Biden’s military appointments.

He abused a mechanism of Senate privilege to do it. "I hope no one forgets what he did." — President Joe Biden thehill.com/homenews/adm...

And they intend to abuse the Parlimentarian too, so Democrats need to start doing some abusing themselves.

iirc - Tuberville delayed many soldiers’ promotions, months of families waiting in limbo about new assignments— all because Biden sought a way to help Female soldiers deployed in Red States access to Women’s rights!