The more interesting question is why Northrop wanted the Dreamchaser and what kinds of missions other than ISS resupply that Northrop might conduct with it. Space tourism and satellite repair and refueling seem obvious possibilities with loads of revenue potential, but other missions also beckon.
Might Northrop develop its own private astronaut corps? And where does Northrop's black budget work fit in? Could a military version of the Dreamchaser be in the works, with Northrop looking to pitch the Dreamchaser to the Pentagon as reliable and proven technology?
You read it wrong. Northrop did not acquire the dream chaser.