Instead of saying “using this term to mean X is a discourtesy”, one could try “please don’t use this term to mean X, and please encourage your readers not to use it to mean X, and to encourage their readers and so on”.
Instead of saying “using this term to mean X is a discourtesy”, one could try “please don’t use this term to mean X, and please encourage your readers not to use it to mean X, and to encourage their readers and so on”.