I would argue the bynars are not doing it voluntarily either though. According to phlox in ENT, right after birth a surgeon removes a certain part of the newborn‘s brain, replacing and connecting it with their central computer.
And I would argue a literal newborn cannot give consent to this. The only difference to the Borg appears to be the larger degree of individuality, though that seems questionable too, considering how interlinked they are in the TNG episode.