You can just kick a person out if their behavior is disruptive. Civil behavior is kind of universal in an enviroment where people's identities are linked to what they say. Codes of conduct only exist to virtue signal and abuse. It leads to Kicking somebody out not because they've negatively affected whatever work is being done, but because some completely unrelated action they've done can be interpreted as violating the project's "moral principles". When people are kicked out on a case by case basis, it's also more likely that a specific reason will be provided and not "they violated the code".