Im going to suggest something again after quite some time and I hope it wont be forgotten like my other suggestions.
Non-active villages are grey, what if you made some color differences on the map with other kinds of villages like those with protection (green mini flag), banned ones (black mini flag) and those that have vacation mode on (blue mini flag)? Is it really neccessary for us to click on those players, choose our attacking unit and then get the memo that the player can't be attacked due to reasons above.
It doesn't have to be a colored flag, just some kind of differenciation from other villages.
With friendly greetings,