Where is the consent of users that are being tracked outside of Facebook and are not part of it? I don't understand why nobody is talking about the even bigger

Where is the consent of users that are being tracked outside of Facebook and are not part of it? I don't understand why nobody is talking about the even bigger issue that Facebook (and Google and every other ad service) gets to see what people are visiting and when (articles, videos, porn, ...)! Imagine the detailed profiles you can create with that amount of data...