I agree. I teach my son adult reasoning and hold him to mature standards. If there is a problem it’s the people who didn’t have any parenting influencing children in a negative way. If my son hears bad language he turns off what he’s listening to and tells me about it. It’s almost like he’s helping me be a parent in a way...that can’t be bad.
No child should be allowed to help parent that is bad. Ratting out others using bad language is not an adult skill. It sounds like your kid has already learned how to cater to your desires. Sounds to me like you have a very bright one on your hands hope your up to the challenge.