Because the term "yapping" is one used only by people who mean to be derogatory. If you intended to deliver a direct insult, that's fine. If not,it pays to find out how the average person understands certain terms, because your intention requires the udnerstanding of the other party for communication to take place. And the burden is on the one doing the communicating.
DO look up Suzette Haden Elgin's blog and writings! Sensible and useful both. She is a retired Professor of Linguistics.