There are still plenty of Koreans, particularly, but not only, older ones, who regard anyone from Jeolla-do or Jeju as a possible "commie". This is part of the reason why some Koreans feel more uncomfortable when we ask them the, for us, normal first meeting question of "where's your hometown?" than we do when they ask us about our age, marital status and what university we went to. It's also supposed to be one of the reasons regular car number plates no longer show their province of origin.
20th century Korean history was quite a sad mess and a some of it made considerably more so by external influences. Much of that mess hasn't yet been completely dealt with historically yet (for want of a better way of putting that). So, as I said above, it's worth being careful about which buttons you press when asking people about certain issues.
Being curious is fair enough, but getting all preachy to people about how they should or shouldn't deal with their own country's history mightn't be such a good idea with people you want to be getting on well with.
