This is because Choryang-dong Wakan was built by the Korean government as the facility for the Tsushima clan, the Tsushima clan was in a position of the window to negotiate between Japan and Korea, therefore Japan did the above acts.
これは草梁倭館は、朝鮮政府が対馬藩の為に建て使用を認めた施設だったこと、対馬藩は日本と朝鮮の間の交渉窓口の立場にあったからである。