Used to express the disappointment in a celebrity sarcastically.
It's often go with a sample paragraph (later translated into many different languages).

Origin:

6/8/2019, on a Facebook site called Rumor – Confession Phim Ảnh Và Idol posted a confession to a famous Korean male singer Kang Daniel from an anomyous fan. The post expressed the disapontment and sadness of this fan when the romantic relationship between Kang Daniel and TWICE's leader, Jihyo was revealed by Dispatch on 4/8/2019. (More information: Dating between idols is considered to be big issue in Korean entertainment industry and also among K-POP fan community)

Example:

When your idol got caught up in a romantic scandal:

I've decided to cất gọn poster vào góc. I will stop being your fan for now.