Because...
게시한 사람 Wout Verlinden 속 에스토니아 공개토론
Because the Russians have always brutally invaded Estonia out of the Estonians will. First in Tsarish Russia and then in Soviet Russia.
In Soviet Russia, the Russians nearly succeeded in exterminating the native Estonian people by murdering them or sending them to Siberia, ripping families apart.
They also feel that as far as politics are concerned, not much has changed, so they still see Russia and the Russians as some sort of an enemy.
Still, I see Estonians and Russians get along just fine every day as well, so it's certainly not black and white. Estonian and Russian values and cultures just are very different sometimes.