“North Korean officials have long expressed irritation about balloons coming over from the south containing political information and cultural products banned by the regime. These packets are generally sent over by private individuals, including North Koreans who have defected to the South as well as activists seeking to foment resistance.
Since North Korean people are closed off from the outside world and have little access to political or cultural information, the South Korean balloons are one attempt by activists to combat these constraints. According to North Korean officials, the trash balloons were meant to show South Koreans how annoying these deliveries are and to push back on these efforts as a whole.
“Kim [Jong Un] doesn’t want his people to know about their relative deprivation and the quality of life in the free world. He is more afraid of BTS than US nukes,” Victor Cha, a Georgetown professor of government, told Vox.”
https://www.vox.com/world-politics/353604/north-korea-trash-balloons