Isn't that their core service?

No, their core service is selling ads.

You can't actually buy anyone's data from Facebook, you can only buy ad targeting.

Oh, okay. I was just confused because whenever I read something about Facebook it was about them selling everyone's data.

That's their core service, they sell your data through targeted means. That is still selling your data.

The only reason anyone would ever call targeted ads "selling your data" is to make people who don't fully understand it believe it's scary. Completely misrepresenting what they are doing.

How about we, as a collective, say it for what it is instead of using words that mean something completely different and let people come to their own opinions instead of thinking for them?

As bad as a news outlet.