Thanks for the question! It is subjective to some degree, but it’s certainly not any kind of wild stretch of the imagination to say that the policy adviser is making arguments based on self-interest here. After all, the policy adviser in arguing for the freedom of speech talks about how good ideas will flourish and bad ideas won’t when there is freedom of speech. And it’s not at all a stretch to think that this is good for the government; in other words, the argument is based on self-interest from the government’s perspective. It’ll be in the government’s self-interest to have free speech because good ideas are good for the government and the society. And so there’s a coupling of self-interest and moral ideals here.
Hope this helps! Feel free to ask any other questions that you might have.