Propaganda does not have to have a hidden agenda. Literally the "I want you" uncle Sam poster is propaganda. That agenda was pretty obvious, there was no question who was behind it and it was pretty clear why it was commissioned in the first place.

There has been propaganda encouraging car-pooling, reusing materials, conserving electricity, promoting employment etc, and many of them even had credits as to who the message was coming from.

Propaganda is not inherently evil, but it's important to understand the context and where it's coming from.