Then why bother scooping up the colony at all? Why not just beam up everyone?
And why DID the Borg destroy/assimilate the Jouret IV colony in BOBW in the first place?
It was a probing mission. They targeted a small Federation colony as an opportunity to learn something about Federation culture and technology without incurring any significant risk. Maybe simply ripping the colony out of the ground and leaving the scene minimized their risk profile and the likelihood of leaving any evidence behind from having drones on the ground for a period of time examining everything.