By definition that is almost every communication that a human makes, whether through art, technical books, education, news, opinion pieces etc. They are all attempts to influence an audience and there’s always some kind of agenda behind it.
> Propaganda is communication that is primarily used to influence an audience and further an agenda, which may not be objective and may be selectively presenting facts in order to encourage a particular synthesis or perception, or using loaded language in order to produce an emotional rather than a rational response to the information that is being presented.[1] Propaganda is often associated with material which is prepared by governments, but activist groups, companies, religious organizations, the media, and individuals also produce propaganda.
> In the 20th century, the term propaganda was often associated with a manipulative approach, but historically, propaganda has been a neutral descriptive term.[1][2]
This is about as rigorous as the questions by those wondering how Facebook could possibly be a monopoly when other websites exist (exaggerating only slightly). Do you know what "discourse" is? It's "how people talk about something," which is what propaganda is designed and intended to manipulate. "Pie tastes good" is not that.
