If you study machine learning, you'll encounter a definition of "bias" that initially seems to differ from the conventional definition, in that a system is "biased" by what it is capable of representing. If I have a simple AI system that I feed two numbers to, "yellowness" and "curviness", it's going to decide a lot of things that aren't bananas are bananas, because the representation that it has access to is very biased and is not capable of representing the full complexity of objects in the real world. This results in a classifier that is very "pro-banana biased".
I say "initially seems to differ" because in my opinion, if you meditate on it for a while, it becomes increasingly clear that the conventional definition is actually a moralistic (in every bad sense of the term) mess, and this definition actually applies very well and clarifies a lot of thought in this area. But that's just a sidebar.
The main reason I bring this up is that I'd submit the reason people are more upset about Facebook is that they find it much easier to represent Facebook in their minds than they do to represent Equifax.
Equifax is, on average... something... something... credit cards? Financials? Ugh. Complicated. I've got no representations for that crap.
Facebook, by contrast, is what I spend two hours a day in. It's what caused that entertaining family drama (depending on which side you were on) last month. It's where I reconnected with... you get the idea. Very easy to represent. Very easy to personify mentally, since the human brain that is optimized for tribal living on the savannas of Africa (more or less) reuses a lot of circuitry for things not in the original design spec, and we use our very capable "model complex behavior as stemming from human motivations" circuits a lot. And that personified Facebook just betrayed you by spreading gossip about you all over the place, without your knowledge (you knew about the rest of what it does), and for their benefit and to your harm. And is being very unapologetic about it.
So there's a whole complex of ideas readily at hand in our brain to understand Facebook. Facebook is basically being modeled as a friend, perhaps even your best friend, who just stabbed you in the back for their own gain. Yup, people are pissed. Where as Equifax was... something, err, people in an office and they dropped some papers on the ground or something? People's brains are readily able to represent Facebook using pre-existing circuitry, Equifax is just a confusing mess that most people can't get a handle on.
Bear in mind that we have a very-above-average concentration of people reading this post who do have the ability to understand Equifax. I'm speaking to the public case here. I also don't think the public is "stupid" on this matter; I just think most people lead lives that involve developing representations for all sorts of things I don't understand per se, but don't involve developing the rather artificial representations needed to understand the unbelievably complex financial industry that exists today.