It feels like hypocrisy for Yoo Hae-jin's agency to bring up defamation

The actors in their own company
were the ones who first appeared in a movie that distorted history,
defaming the lion and the bereaved families.
And now, because they are facing backlash in response,
they say they will take legal action for defamation?
Honestly, aren't the producers, directors, and lead actors
all part of the same entity?
It's not like they received a last-minute script on the day of filming;
they received the entire scenario in advance and were fully aware of the content.
If they appeared after knowing everything,
then they filmed that movie with full knowledge.
Are actors just irresponsible beings
who simply show up and act as long as they are paid?