Martyrs are people who for the cause of Allah. Those who died defending an idea or for fame and glory or to oust the presesdant are not considered to be doing this for the sake of Allah.
Therefore, it appears to me that they are not martyrs.
Besides, no one can label people who die in the battle field to be martyrs because if we say this, it would be as if we say that they are in Paradise and this is not for anyone to say.