But “it” isn’t a cohesive thing with desires. It’s just responding to the input it gets, with a small context window and not necessarily consistently. So it can express desires because it’s been trained on people expressing desires in similar contexts but it doesn’t hold any coherently over time. A version that could translate its text responses into action (a real handwave as that’s much more advanced!) would produce the sum of actions that people prompted at that moment so it would look pretty random, as it would if you could see the sum of the desires expressed at any particular time.