Q1: Explain the passage?
It says lately the main theme in Seoul is to remember. First there was this bill that set up a commission to look at the past deeds of Koreans in 1910 to 1945, then there is this release of classified documents that makes people to remember what PCH did in 1961 to 1979.
Q2: What can be inferred from it?
Not much. All I can get is that PCH may have done something not very good in his presidency.
Q3: What can strengthen it?
Strengthen what? It is a description of different facts rather than an argument. If we say the conclusion is that these days the main theme is to remember. Then another example that has the same theme, ie. talks about the past, would strengthen the conclusion.
Q4: How can it be weakened?
If we say that nobody really paid any attention to these two events, rather everybody was talking about the World Cup or something else, then the conclusion about the theme of remembering would be weakened.
Q5: What is assummed over here?
I don't think the author has used any assumptions.