One problem is AI interactions moving the goalposts of what folks may perceive as 'douchebag'.
An AI providing sycophantic reinforcement at max makes someone being vaguely skeptical of you feel, by comparison, like they are being a 'douchebag'.
Sometimes, it's best if people in your life aren't always acting in a way that seems supportive and positive in the moment. For example if you are having a paranoid delusion, you need a reality check rather than what feels like external validation.
Talking to yourself keeps the perspective hopefully grounded, you know who you are talking to and how full of shit they can be. The magic of AI seems to peel that grounded perspective away for some folks.
Of course that's true, the issue is that when folks are surrounded by "yes men" (or AI equivalents), they lose perspective and suddenly a lack of flattery is enough to be in the "douchebag" category. Some reasonable social friction is important to keep people from going way off the rails.