Japan was shocked by President Lee's recent visit to Dokdo.
In the history of constitutional Korea, it was the first time a Korean president in office visited Dokdo. So it may be shocking for Japan, but it is a Korean president going to Korean island, Dokdo, not any other country's president. So all the criticism and complaint from Japan implies that the Korean government has been too complacent in dealing with Japan's ambition of Dokdo.
The Japanese government has stated in the Defense of Japan white paper that Dokdo is theirs for 8 years since 2005. However, the Korean government merely expressed complaints toward Japan, a very lackadaisical action that was too conscious of the Kor-Jap relationship.
The reason the Korean government passively counteracted was to prevent itself from following Japan's intention to make Dokdo a disputed territory by putting the spotlight on the small island. However, it is time for a change. The Korean government must show a stronger actions.
Japan plans to take the Dokdo issue to the International Court of Justice. However, if Korea rejects the offer, there won't be an ICJ trial. This is because when Korea became a member of ICJ, Korea did not accept the compulsory jurisdiction. Japan's threat to sue Korea is a trickery by Japan's ruling party to increase its approval rating.
Dokdo is in effect Korean, and Korea needs to react stronger against Japan.