The element people are ignoring is money. You can communicate, teach, etc. without money coming into the picture. Sales is about money. You can claim you're "selling" an idea, but the implication is that you're still doing it for your own benefit or advantage. That doesn't mean it has to be a one-sided transaction. You may really believe that what you're doing is beneficial for the other party. But your own interest is an inextricable element of sales.
If your own advantage isn't a factor, there are a hundred words with more relevant connotations to describe what you're doing.
If your own advantage isn't a factor, there are a hundred words with more relevant connotations to describe what you're doing.