It depends on how Islamofascism is defined.
Break it into its components. Islamic + Fascism.
Islamic - This fits, they are Islamic.
Fascism - This doesn't. They aren't nationalist and the similarities between nationalism and theocracy (ie centralised command) don't justify the use of the term. There are similarities between nationalism and patriotism, but patriotism isn't fascism.
There are similarities between a cat and a cow, but the names aren't interchangable. (This isn't a strawman, this is an analogy to make my point)
Describing these theocrats as nationalist isn't valid. Nationalism is promotion of the nation-state and that isn't the goal of these theocrats. It isn't a nationalist theocratic dictatorship because the concept of the nation state isn't important to these theocrats.
Soviet Russia wanted to unify the world under the Communist International, a centralised dictatorship, but they can't be described as nationalist. (Again, not a strawman, but an analogy)
So nationalist doesn't describe these people well, but then fascism isn't just nationalism. Fascism is the amalgamation of nation state and commerce.
Islam is traditionally a religion of trade and nowhere in the Islamic theocrat's ideology is the amalgamation of any nation state and commerce suggested.
Thus fascist is a poor description of these people. They aren't nationalist, nor seeking to amalgamate nationalism with commercialism. The only similarities between the theocrats and fascism is a preponderance for centralised authoritarian dictatorship and as we has discovered, that is a similarity that they share with many ideologies, it is not a defining quality.
So we have to ask, why would politicos use such a term? The obvious answer is as a rhetorical device, to create pathos. Fascism is a term that, due to the actions of fascists in the C20th has rightly a negative connotation and attaching it has far more impact that using the correct term, Islamic theocrats.
