To call torture 'enhanced interrogation' avoids the use of the word torture because it has negative connotations, and tries to normalise torture by association with an accepted practice (interrogation), after all interrogation is what you do to prisoners isn't it?

It's a clear distortion of language to hide the truth; it has everything to do with language and the use of it, as it deliberately twists meaning in order to limit the thoughts of people who accept this term to describe certain actions. As Wittgenstein put it:

The limits of my language mean the limits of my world