Based on that definition, schools share propaganda by simply educating pupils. Teachers spread information for a certain cause: education. A top-notch education generates a good reputation for their schools (schools are institutions).
i.e. In Indonesia, we're often taught to loathe the actions done by Dutch people, since, you know, 350 years of colonization -- through History and Civics. The actual stance of modern-day Indonesians will be each to their own, though -- Indonesia and Netherlands' modern relations are relatively positive, even.
We are also taught that Japanese colonization was even harsher than the Dutch, yet Japanese culture has colonized the country positively in modern-day Indonesia.