> many don't like FB but have no idea WhatsApp belongs to FB

When you start WhatsApp the splash screen says "WhatsApp from Facebook" so I would be surprised if people really didn't know that the two companies were related. Instagram is the same, it says "Instagram from Facebook".

WhatsApp: https://i.imgur.com/JS20lGJ.png

Instagram: https://i.imgur.com/1SWybdu.png