There are still a lot of things that users on steemit don't understand especially new ones... usually you learn how things work as you go on using steemit, or at least that is how I learned them.
The ones that don't understand how voting works and what is the idea of the curation rewards, should just try to learn more about voting power by reading or asking. If they are not willing to do even that, then well, let them vote as much as they want, for what they want, when they want, and they will just learn it the hard way... or not learn it at all and leave disappointed because they are "not making money on steemit".