Usually people use words so that other people will understand them. If your internal definition doesn't match nearly anyone else's, maybe you're using the word wrong.
Isn't that all language is? An appeal to what others think you mean? This ofc is why people like to push definitions in different directions. I think you're saying, "Christian should mean XYZ," while I'm pointing out most people don't hold your meaning. If you want everyone to adopt your definition, you need to give a compelling reason. However, I've heard so many other people who call themselves Christian claim that all the other so-called Christians are not really Christian, that I don't really trust any particular Christian's definition. It's easier to just say, "Christian means someone who claims to be Christian".
