Is it permissible to describe the Muslim Brotherhood and Salafists as exploiting religion to reach power?

Mistrusting Muslims in general and those working for the religion is not permissible Islamically. It is also not permissible to accuse brothers of being worldly seekers who trade with religion. The basic principle is to have a good opinion of a Muslim and interpret their actions in the best possible light. One must be wary of the peril of the tongue. The apparent state of most members of these groups is goodness and an endeavor to establish the religion and implement the Sharia, which is an obligation upon all Muslims. It is advised to refrain from [speaking ill of] your brothers and to cooperate with them in righteousness and piety, and not to confine truth to the methodology of a single group. Their work is human, containing both right and wrong, and defamation campaigns against them aim to prevent the spread of the light of their reformative call.