They even went to a U.S. court to catch the person who left ridiculous malicious comments about IU, calling her a Chinese national and accusing her of plagiarism.

There was a malicious commenter spreading false information by linking ridiculous rumors to the Sewol Ferry disaster and the Itaewon tragedy.
Since they couldn't identify the person in Korea, they even filed a request for information disclosure with a court in California, USA.
I am truly furious to hear that someone spread marketing about the deceased that crossed the line, and even uploaded 52 instances of rumors that went too far.
I hope they show absolutely no leniency this time and track them down to the end to make sure they are properly punished.