The theory-theory contends that when we attribute beliefs to others in order to explain and predict their behaviour (mind read) we use a a folk psychological theory. What is a good reason to object the use of a pure theory-theory?
The theory-theory (or theory of mind) is generally considered a successful (even indispensable) theory throughout history, such as contemporary functionalist Jerry Fodor. The pure TT hinges on the fact that the attribution of mental states to another mind is justified only on folk psychological conceptual level theory without any use of lower-level imaginative simulation. No wonder Fodor endorsed it since he's a strong proponent of the hypothesis of a private internal language of thought (LOTH).
However, a major argument against TT from Simulation theorists (such as Robert Gordon and Alvin Goldman) argue that folk psychology is not a theory, but rather depends on internal simulation of others, and therefore is not subject to Popperian falsification in the same way that most scientific theories are. Also from ST POV when we explain other's intentional states and actions we don't draw on any psychological theories instead we employ our own decision-making capacities and imagination skills, which is fundamentally different from explanation of natural sciences generally.
Another argument from cognitive Eliminativism argues that the common-sense laypeople understanding of the mind is mistaken, and that the neurosciences will one day reveal that the common mental states such as "intend", "believe", "desire", do not refer to anything real. Because of the inadequacy of natural languages, people mistakenly think that they have such beliefs and desires.
Eliminativists argue that discrete and combinatorial characteristics of psychological theory have no place in the neurosciences, which speak of action potentials, spiking frequencies, and other effects which are continuous and distributed in nature. Hence, the syntactic structures which are assumed by folk psychology can have no place in such a structure as the brain.