Consider the following definition of "psychological manipulation" from Wikipedia:
Psychological manipulation is a type of social influence that aims to change the behavior or perception of others through abusive, deceptive, or underhanded tactics. By advancing the interests of the manipulator, often at another's expense, such methods could be considered exploitative, abusive, devious, and deceptive.
Note that the ethical problem is not with the manipulation itself, but with the reasons for the manipulation. Was the manipulation done through "abusive, deceptive, or underhanded tactics"?
A positive form of manipulation might better be called "social influence". The same article describes that:
Social influence is not necessarily negative. For example, people such as friends, family and doctors, can try to persuade to change clearly unhelpful habits and behaviors. Social influence is generally perceived to be harmless when it respects the right of the influenced to accept or reject it, and is not unduly coercive. Depending on the context and motivations, social influence may constitute underhanded manipulation.
Although "underhanded manipulation" exists, it is possible for social influence, perhaps interpreted generically as manipulation, to be "harmless".
One could view ethics as a form of manipulation or social influence. That in itself should not make ethics unethical simply because it is influential. Influence need not use "abusive, deceptive, or underhanded tactics".
Wikipedia, "Psychological manipulation" https://en.wikipedia.org/wiki/Psychological_manipulation