Popper's philosophy is not necessarily straight forward empiricism; his key concept is falsifiability. A hypothesis or model is legitimate if it can be proven false. If there is no rational possibility for refuting it then it is essentially useless to the progress of science.
I understand but some people use poppers tool as a way of proving or disproving a theory, even when that theory might not good for scientific testing.
Of course people would use it since it is practically invaluable, but if a theory's 'not good' for scientific testing, it's either not scientific, or it's not within the domain of science to test it.