They need this information to provide the services they offer, if you don’t want the services don’t provide the data. I thought I made it abundantly, crystal clear I am against them arbitraging or selling this data for other purposes of the kind you describe. That’s what we need to focus on with regulation. Of course they want to use this data for other purposes, and we need to make sure they do not. I find it somewhat exasperating that you seem to think I believe otherwise.
So you don't like Cambridge Analytica, but Google, Twitter and LinkedIn using your data for goodness know what purposes is fine? I'm pretty sure they're running all that data through all sorts of machine learning algorithms and some of that might be used at some point for surveillance and censorship purposes or dystopian stuff in general. Not might, will be, if already isn't. Because you'd have to be stupid to have this amount of data and not use it to further your political agenda.