Seriously, imperialistic? Which nations are South Korea trying to attack and add to their Empire?
South Korea is a bustling, free, democratic republic where people are free to change jobs, worship as they please, entertain themselves, elect new governments, etc. etc.
Does the South have crime, corruption, problems? Of course it does. Anywhere several humans gather for any period of time will see such things will creep in. But they are pretty well controlled and the criminals, even governmental ones, are brought to justice.
The North, on the other hand, is a hell hole, very poor, total control, ruled over by a despot and tyrant with death camps, brutal secret police, interment camps, starvation, etc., etc.
If you have to think for an instant about which place you would rather live, you do not understand the realities of either.