Propaganda is a character "vice of excess" stemming from what would otherwise be a character virtue of Inspiration. It is too much Inspiration about achieving a goal, to the degree that the partner issuing it is likely trying to control or change the other partner in some way, to fit their own life's goals - their "mission in life" or "purpose in life" - to actually become that of their partner's. It is intellectually narcissistic, whether directed toward the self or toward others, which is to say that it contains either the intellectual narcissism of ignorance or prejudice. It is also part and parcel of codependence, which is a state of too much shared intimacy and outright bullying by one partner toward the other.
As in most failing partnerships, one partner may be prejudicial against the life's goals and dreams of the other, as if those were a threat to their own. It is part of the definition of pathological narcissism to have a world-view that is "win/lose" instead of "win/win." This is to say that someone else living their dreams is seen as a threat to your own, which is destructive to the whole relationship, and cuts off the partner as a unique source of creative solutions and efforts that actually benefit YOU if they achieve THEIRS. At least with the other vice, Resignation, you may go about your business of pursuing your dreams, even if they are sabotaging their own for a time. But with Propaganda, the partner is actively trying to change your dreams into something other than your dreams.
Someone who issues "propaganda," is by definition, controlling in nature, of poor boundaries, narcissistic, and disregarding of the sacrosanct nature of your "purpose" or "mission" in life. Your life's goals and dreams are the most precious things you have, more even than the romance itself, or the welfare of your children. Without your dreams, you have nothing to give children, actually. Propaganda directed counter to the goals and dreams of a mate shows poor boundaries and a lack of respect for the very life of the other person, beyond even their ideas or emotions. It is their spirit itself - their masculinity or femininity - that is at risk of being hijacked or depleted, and needs Inspiration as its cure.
As a vice which makes partnership within relationships fail to get to goals, and intellectually unattractive, consider this vice to be negative in many ways, including in sexual attraction, since it actually depletes the reserves of one's own, or the other partner's masculinity or femininity, making them less attractive and feeling less attracted back to you.