I think a better analogy might be "If I take a few hundred thousand MP3s and come up with a clever way to reduce each to a short representation of its genre, mood, tempo, etc that can be used to identify similar music, then throw away all the original MP3s, am I still in possession of the original music". The whole point is to turn the individual data into broad, general categorisations that are easier to handle because they contain much less information. Remember, they're using this for ad targeting, and the reason they're doing it is so they can target broad groups of people rather than having to manually go through and target ads at each individual one by one.
I like that analogy. I'll make it more tenuous with - "I took a copy of your album collection without your permission, ripped them to MP3, played them so much everyone is sick of them. but you've still got all the original CD's you don't even use, so no problem right?"
On this tangent, IP ownership for deep learning models is interesting - how to you prove (in court) someone has/hasn't copied model/stolen a training set? If you fed someone else's training/model into your system, how easy is it to prove? Will we see the equivalent of map 'trap streets' in trained CNN models?
Except Facebook let them take a copy of the album collection, albeit for a different use case, but it was allowed nonetheless. That doesn't absolve CA in any way, but should make us wary of people we willingly give our "album collections" - they will use them to make money, and what they allow people do with them can easily be things we don't agree with, but didn't have the imagination to think of when we signed the EULA.