It's hardly a slur to call Modi a fascist. He is one. Parts of India have also had democratically elected Communist governments.
Technically, a "fascist" is a person who advocates nationalizing the goals and direction of the means of production while leaving them in private hands is? Clearly, the term "fascist" has been bandied about here as a subjective slur as opposed to an objective technical description of his economic policies.
Technically, 'fascist' is a term debased of all meaning by common usage. You may as well be insisting on the technical use of the term 'imbecile'