Even more specifically, the God of Lies in "Q Who?" suggests the Borg are only interested in technology.
Remember we're talking about a TV series here. Which means any information given to us by a character we have to take as gospel because it is the only information we have to go on. There's no otherway to expositly deliver the information that the Borg are only interested in technology than to have Q and/or Quinan tell us. We have to take their word for it.
So either the writers for Q-Who knew what they were going to do for an episode that wouldn't be written for another year and a half and had Q lie about the Borg or they simply changed their minds for story purposes on how the Borg worked.
I personaly believe the second one and reconcile it by saying that the encoutner with the Federation changed the Borg into an asimilating culture (exactly what the Federation does). Which has a nice poetic symetry to it. Unfortuantly Voyager's PTB didn't have any sense of this dramatic irony and either completely ignored it or it never dawned on them.