> A sense of morality or just any connection to what's... normal?
Regular reminder that what is moral, what is normal, and what is legal are three separate questions with time- and culture-specific answers.
This stuff is "abnormal" only because it's new and no norms have been established. Using an AI for anything cannot be a "normal" act because it's so new. This is the possibly dark side of "disruptive".
The more relevant question is: is it harmful? And you might construct an argument that leading people into delusional beliefs is harmful.
(of course, then the free speech absolutists turn up and say that by definition nothing Replika says can be harmful because it's just speech, and it would be morally wrong to intervene in the conversation between a company and its users)