In what way? I've read quite a bit and still can't get it. Also "influencing elections" is a funny thing to define. I know these days every joe and mary walking down the street is protecting democracy and whatnot, but the Cambridge Analytica debacle was just politicians learning about APIs from my current understanding. Anyone using the FB API at the time could have done the same if they infringed the terms in the same way CA did.

Are campaigns influencing elections when they use credit card purchasing data and so on that they buy? Why isn't that the same scandal?

I do, before there was a sea of games on facebook, before facebook apps, people were clamoring for the API access. It was supposed to be the next big thing and everyone made integrations with it, you'd log your spotify listening queue to it, etc. Developers were very happy when the API came to be. Then later people became aware of how much access you could actually get and especially if you saved the data locally. Then the FTC fined them for it and everyone tightened things down, not just Facebook. I at least remember it like this, with that first part.