"I only trusted my manager" — sold savings to buy stocks, lost 20 million won [How do you see this?]

[Financial News] An office worker who invested in stocks at the urging of a supervisor said he suffered losses worth tens of millions of won and felt wronged. He said he bought the stocks his boss recommended and ended up losing most of his principal.
A post titled "I lost 20 million won because of my manager..." was recently uploaded to an online community.
The writer, identified as A, said he was a conservative investor who usually managed his money through savings and time deposits. He claimed that since last year, he had repeatedly been urged to invest by his supervisor, Manager B, who had long experience in stock investing. A said he turned the advice down, but B told him, "If you don't invest in stocks in times like these, you're an idiot," showed him his own profits, and strongly recommended specific stocks.
A eventually canceled his savings account and invested more than 20 million won of principal in the stocks B recommended. He said he then trusted the remark that "stocks like this need to be viewed over the long term" and did not check his account often. When he opened it again some time later, he found that he had lost about 13 million won in that stock alone. Including other small investment losses, he claimed his total losses reached 20 million won.
When A asked about the situation, B reportedly replied, "I sold part of my holdings for a profit when it recently went up a little."
A said he felt hurt and asked, "Why didn't you tell me when you took profits?" B then reportedly responded, "I only did that because my average purchase price was lower. I am not obligated to share every detail of how I manage my account. In the end, you made the decision to buy it yourself," taking the position that he could not share responsibility.
A said, "I am not trying to demand that he pay me back, but it is so frustrating to realize that the person who kept pushing me to buy was secretly taking profits himself." He added, "At the very least, I think he should have said one word when he sold, so I feel bitter about it."
[email protected] Han Seung-gon Reporter