if u read the early chpts its explained what Banana means (its an insult used against asians who are "white" on the inside. namely the korean american students who felt at odds with the korean students who mainly grew up in SK)
because "banana" refers to taehee being "yellow on the outside but white on the inside" which is a racist joke （￣へ￣）some characters call taehee this earlier on in the story (please correct me if im wrong)
omg sorry i just realised somebody else already explained
HOW IS THIS CALLED BANANA SCANDAL? THE DICK'S LOOK LIKE SAUSAGES LMAO, NO HATEEEEEEEEE JUSTTT SAYINNNNN(づ￣ ³￣)づ