This article specifically talks about sex workers using whatsapp and the fact that because of meta data sharing, IF a warrant comes from the government to find users associated with a certain group (such as sex workers groups) on Facebook, it indirectly brings whatsapp users into that group as well through indirect means. Interesting issue yet so many "if"s. The reality is that Facebook needs to make money from whatsapp at some point. If keeping end to end message encryption is important, then they are left with three equally bad options:

# Charge for the service (whatsapp will lose 90% of its userbase in a month)

# Show generic ads (worse value than even TV ads, because at least TV ads know a little bit about the viewers of a certain show but whatsapp has no idea)

# Figure out a way to deliver targeted ads.