Yes, there are Communist supporters of the DPRK in ROK, but that’s not what’s at play here. President Yoon, the Incel King, is accusing the liberals opposing him in Parliament of being Communist sympathizers. Yoon himself has been saber rattling against the DPRK as well, but that again is not the crux of the situation here.
Korea, over the last hundred years, has been victimized by Japanese and American Colonialism, Imperialism, and has been split in half arbitrarily, been the focus of a brutal proxy war, had the entire peninsula bombed into oblivion, and families torn apart. There is a deep cultural desire among both sides of the 38th parallel to reconcile in some fashion. Economically, it would be nice for both sides to engage in trade with each other, but it isn’t the core of the matter, plus the DPRK is no longer in the serious “struggling phase” it was in in the 90s and 2000s, and is more like Cuba these days.