That would mean that you thought that the Borg went to the effort of copying lives only to erase them. Either Hughs life was so fantastic that his planet was put to the sword to get it, or it was so valueless that it was inconsequential chum caught in the Borg War machine taking over the Galaxy.
Do the Borg brainwash or educate?
When the Borg talk, it's not one Drones opinion, it's all of them in consensus....
Consensus or majority?
Imagine if initiate assimilies have an equal vote as every one else to create change but not the numbers, however the longer they spend inside the collective the nicer it seems.
The Borg Queen kinda fucks up this later season TNG era assumption.
I didn't think that Hugh was brain washed, just that he had never experienced a different opinion (or never remembered experienceing a different opinion...) other than the Borg agenda, which was benevolent and charitable bringing the gift of assimilation to all the down trodden, no different than missionaries bringing the voice of god across the globe today.
Although if I was to take something from your recognition of the facts Exodus, I might think it's possible that Hugh had been wiped clean, perhaps because he wouldn't get with the program, or just a glitch, but the ease with which he befriended Geordie and helped the Federation screw over his species, says that he was not forcefully programmed to be unreasonably loyal to the Borg.
Hugh was only reasonably loyal to the Borg.