It's pitiful and no one likes it.
If you trusted a person and gave them your access credentials, it is your personal responsibility, not the owners or developers of the game. It could also happen to you in real life if you leave the keys to your house with a neighbor to take care of it.
If you trusted a person who later proclaimed himself Commander-in-Chief and expelled you from the alliance, it does not feel good but it is not against the rules of the game. If your teammates were happy with you leading the alliance you should found a new alliance and invite everyone there except the one who betrayed you.
Just as that person manipulated you, he may have manipulated the rest of your classmates and made them believe something inappropriate. You should figure it out with them, game owners or developers don't have much to do here.
The downside of creating a new alliance is that the game won't let you use an alliance name that already exists on the server, even if no one is using it now.