This seems like such a bizarre thing that you’d only see in a low-budget, awful movie…and yet, once again, reality in 2024.
Having lived in S. Korea for 4 years and understanding a bit about the culture and people, this strikes me as a 100% normal thing to do. S. Korea recently sent a barrage of anti-North leaflets over the border. So N. Korea is saying, “You sent us garbage, so we are sending you garbage.” This will actually be quite upsetting to Korean citizens, it’s a symbolic slap in the face. It is hurtful to S. Korean people and yet S. Korea can’t really strike back since it is “harmless”. It’s actually kind of brilliant.