Facebook paid a boat load of cash for WhatsApp. Why did you think they did it? out of the goodness of their heart? It's a business, people! and if you are not paying for it, their revenue stream must come from somewhere else. You are the product as much as the user. Get over it. If you don't like it, don't use it. Use Signal instead, which I do, and it's great.

There are also alternatives like Wire, which is really good although it doesn't have the adoption WhatsApp has.