What is the ruling on not informing friends about the the ruling on subliminal messages after learning of their prohibition, and does a person become a disbeliever if they do not inform them?

Clarifying the ruling on (subliminal messages) for someone who believes in its effect as a communal obligation (fard kifāyah), and that it becomes an individual obligation (fard ʿayn) if no one else performs it. However, not explaining it to friends is not disbelief (kufr), and this is a form of waswasa (whispers/obsessive thoughts) that should be ignored.