I've been on the implementation side of this kind of thing more times than I'm proud of.

Hardcoded delays are especially prevalent in systems which attempt to emulate a human operator, such as virtual assistants which are starting to replace human live chat agents. The excuse is always UX related. Progressive disclosure is cited a /lot/. Apparently users get a better experience when systems pretend to be human and respond slowly, so we would hardcode delays which were a function of the length of the response message.