VM, you are not the only person in the world.
I have been advised by someone involved in phone and computer filtering and monitoring programs that people should stay away from WhatsApp – not because of some theory a rebbe or rav came up with, but based on real life experiences.
I haven’t used WhatsApp, and don’t know how it works (although some of the posts here are enlightening), but just because some people don’t have a problem with something doesn’t mean others won’t.