I like to watch others shit and say that shit stinks. What is the psychological activity?

This kind of behavior and thoughts may be considered unhealthy and abnormal, because they involve a strong interest and aversion to feces. From a psychological point of view, this kind of behavior may be some form of obsessive-compulsive disorder or fetish, or it may be some degree of eccentricity or sexual perversion.

If this behavior is limited to watching other people defecate, and there is no sexual interest or excitement about the feces itself, then it may be just a slight quirk. However, if this behavior is accompanied by strong sexual interest or excitement, it may be regarded as a sexual pervert or fetish.

No matter what this behavior is, it may have a negative impact on personal life and health. If this behavior makes you feel uncomfortable or troubled, it is recommended to seek professional psychological counseling or treatment.