"Well, leave!" isn't an option. They can't leave. Quitting Facebook when you're an active user means you lose a huge amount of social contact. I can think of a dozen people I know who are there because it's how they send baby pics and the like to family. They're non-technical and don't care about federated mastodons, they just want to see their niece and go to their high school reunion.
So yeah they get really mad at this stuff but the network effect is so strong, you can't simultaneously convince the entire graduating class of whatever to plan reunions via some new thing when 1)everyone's already on facebook and 2)they've been using it for so long it's part of their workflow.
The answer is the same with any other foul business practice you oppose. The problem is not unique to digital businesses and I really hope those demanding justice don't request something more brash than they otherwise would in a non-digital situation.
And yes they can leave. There are real things you can't leave like your only ISP (internet is essential in modern society and no alternatives), then there are websites you can choose not to leave like FB (not essential in modern society). Your misuse of the word "can't" instead of "won't" just discourages any level of consumer responsibility.
Yes, of course everyone can always leave. The only price - for more than a few of those 2 billion - is the complete disruption of their social lives. Telling someone they can never see cute pics of their lil cousin again is punishment, not a serious decision about consumer responsibility.
You can tell because a history of malfeasance and yet, 2 billion active users.
I guess I'm old, but I find that email is great for sending baby pics to friends and family, and for planning things.
so solve for that, not your dozen or so social group.
"We are required to notify you that we have leaked information from your account, please be advised that we have no idea who has your profile information, pictures, post history or any other information contained in your posts. Please consider resetiing your entire online persona to avoid financial and/or social consequences."
With two buttons: "Erase me from Facebook" or "I get it, I don't care."
Just planting seeds, Bill Hicks style...
The fact that they don't leave mearly show that they value the gained social contact higher than the cost of data breaches.