I thought TNG already established they previously assimilated other cultures with "We will add your biological and technological distinctiveness to our own"
That came in "BOBW", in "Q Who" they were only interested in technology.
It was TNG itself that changed the Borg, not VOY. TNG couldn't make up its' mind whether the Borg always assimilated people or not. All VOY did was run with what it was given.
Oh I know TNG changed them between meetings but something happened there that COULD explain the change. But Voyager ruined that idea by suggesting the Borg had ALWAYS being doing this which simply only ruined my interpretation of things to compensate for the discrepancy. The meeting with the Enterprise "changed" things apparently as before that moment the Borg were "neither male nor female, only interested in technology" after the Enterprise they were interested in assimilating cultures (which is, on a basic jaded level, is what the Federation does) so "something" changed with the meeting at System J-25. And it'd be a beautiful bit of harmony if "my idea" was the route they went with. (Which may very well have been their intent) But Voyager made it so the Borg ALWAYS assimilated people and cultures so the ship at System J-25 is the odd one in the group that only wanted technology.