夾帶私貨

China's internet slang term 私貨 is used metaphorically to describe content that is clandestinely inserted into a formal statement, discussion, or piece of work. It refers to personal opinions, non-mainstream content, speculation, over-interpretation, or irrelevant personal preferences that an author or speaker "sneaks in" under the guise of an objective presentation.

 私貨：The subjective, often irrelevant, and sometimes biased content that the speaker inserts.
 夾帶私貨：The act of inserting this personal content.

For example: 

 這篇影評夾帶了作者對某明星的私貨。

 This movie review included the author's personal opinions about a celebrity that were unrelated to the topic.

The reason for the initial confusion (I thought the celebrity was arrested) is that the term 私貨 is similar to the term 走私/走私貨) has a completely different meaning in Taiwan.

In Taiwan, 走私 is primarily used as a verb, emphasizing the illegal act of secretly transporting goods across national borders to evade tariffs or import/export restrictions.

 走私 (v.): To smuggle. (Emphasizes the action.)

 走私貨 (n.): Smuggled goods. (Refers to the illegal product.)

For examole: 

 海巡隊在高雄港登檢一艘貨輪，查獲市值逾4000萬走私菸品。

 The Coast Guard boarded a freighter at Kaohsiung Port and seized smuggled tobacco products valued at over 40 million dollars.

So now we know that in Taiwan, these terms are used strictly in a legal context to refer to illegal physical goods and the act of transporting them. In China's internet slang, however, the term "私貨" is used metaphorically to describe non-objective ideas or biases that are subtly disguised within a piece of speech or writin a piece of speech or writing.