While its easy to point at Facebook and say "they are so creepy" - this sounds like the type of challenge every marketing department faces. "What is the attribution of X,Y,Z ad campaigns?"
Connecting purchase + email + 'where the ad happened' via social solves that.
That can still be creepy. (If you're meaning that the accusation of "creepy" should be directed at modern marketing in general and not just Facebook, yes, I'd agree with that, though a good part of how we got here is large centralized aggregators like Facebook.)
I think there are plenty of non-advertising contexts where "using people's data to influence their behavior more effectively" can easily cross from normal to creepy as you start collecting more data. If you give your SO a certain flower because you remember a conversation the two of you had a while ago about that flower, that's normal and even thoughtful. If you give your SO a certain flower because you hired people to follow them before you even started dating and you got a report that they always stopped to admire a certain flower on their walk to work, that's creepy.
1. Is that ok that we accept this sort of Pavlovian training from anyone, much less for-profit companies?
2. Is it ok now that the entities are so easily able to completely track the effectiveness of their advertising and thus empowered to amplify whatever works to increase their success rather than some metric like human happiness?
There's new data privacy regulations at the state and federal level going into effect which is why FB made these changes, but they don't explicitly prevent this kind of data sharing from an outside company using first-party trackers to send data to Facebook's marketing platform.