We use words to communicate effectively with other people. If different groups use words differently, that creates confusion and works against effective communication. We need to come to a general agreement about what words mean so that we can effectively communicate. If you decide to deliberately use a word differently from how it's been commonly used, rather than accepting the fact that you've been using it differently from everyone else and changing your behaviour, that makes effective communication harder.

> If people use it in this context, it means this thing.

to them, it means that thing to them