The founder of Whatsapp said that he would not use the product, due to privacy concerns about what Facebook did after acquiring it. If the founder is not willing to trust the product, I'm not going to trust it either. Sometimes I wonder how people could still use Whatsapp despite this fact. But I guess this fact been memory holed somewhat. I'm having trouble finding articles that come right out and say it, but many come close e.g. https://archive.fo/xetmQ