People write here without knowing South Korean law. In this country, it is not only illegal to possess drugs, but also to use them. And not only in the country, but also when a citizen of this country uses them outside his country. It's the same with gambling. Koreans are not allowed to gamble not only in their home country but also abroad. As for this actor, Yoo Ah In, according to Korean law, he is a criminal then, it's not just a matter of his "cancellation".
No drama or movie, etc., should be more important than the memory of a nation and its history. Koreans made their decisions on dramas. These were their decisions and drama audiences from other countries should respect them. I think it's good that South Koreans are fighting for their historical truth. This is how nations retain their identities.
Patriotism is what protects the nation. Patriotism is never overzealous. People should know to be responsible for their country, know its history and take responsibility for it. They should not allow history to be played with in the name of entertainment.
You write the typical gibberish of people who want others to disrespect history. History is the most important thing that keeps humanity from making the same mistakes. Those who do not know their history and do not draw conclusions from it do harm to their nation. You need to know everything about history, good and bad historical moments, to create a healthy nation that is accountable for its actions. Because nations are responsible for themselves, not just their leaders.
It is not illogical to protect your own country's history. People from totalitarian countries probably don't understand it because they are brainwashed and their Masters lie about the history of their countries all the time, but those from democratic countries understand, or at least should understand, how important it is to respect the history of their own country and not allow it to be distorted in the name of entertainment.
" woman who believes in love once again after having two failed marriages. " What does it mean? She was widowed twice, because divorce is not an option in historical drama. Or that she almost got married twice, but something prevented her from getting married?
Why do people call it "period dramas". It is pure fantasy and has nothing to do with any historical times. "Alchemy of Souls" was a pure fairy tale about magic.
I was hoping it would be a short, action-packed drama (something like "Revenge of others"), but given the name of the writer, I should have known better.
No wonder the patriarchy is blooming, and in some countries women are killed because they don't want to cover their hair. Often the women themselves uphold the patriarchy, they will, for example, be fans of bad men and defend them are part of the millennia of complicity in destroying other women. To the female fans of this actor: instead of being a fan of a man, find yourself some actresses as your favorite and devote your time to them.
There's nothing better than liking actors who treat women badly, right?
If you are a man I understand that you are defending the same type of men as you are, but if you are a woman I do not understand and it is sad that there are women who defend men, those who treat women badly.
K-Drama 
What does it mean? She was widowed twice, because divorce is not an option in historical drama.
Or that she almost got married twice, but something prevented her from getting married?
To the female fans of this actor: instead of being a fan of a man, find yourself some actresses as your favorite and devote your time to them.