"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.
