Since you have not given any reference to the declaration you're talking about, i'll just go and try to help you how ethos could appeal to a speech or essay. Ethos refers to the credibility or personality/character of the speaker. For example, someone who has been through the World War II can be appeal to ethos when it comes to his experiences in it and to persuade you to do diplomatic negotiation instead.
The answer is: it lacks information and details.
The opening sentence line of an informative essay should include further information and details, especially from authorized sources. The reason is the writer must convince readers to continue reading and provide evidence to support his or her point of view. Therefore, the audience will consider the text as a valuable reference and will be more likely to be persuaded by the author's perspective.
