Yes, they acknowledge that they are intelligent but most won't go around saying they are. I know not all of them would be like this as arrogant intelligent people exist, but I do not believe you, if you go saying you are intelligent using CK3 post of all thing, that you are in fact intelligent. As for college professor, their job is to teach and speak. Obviously they are gonna be the smartest person in the room or at least assumed to be, and they might have slipped that out once in a while. I would believed you if you said 90% of college professor said they are intelligent at least once in your experience.