This is a tough one. On the one hand, fuck facebook.
On the other hand, interacting with facebook from your own instance is a more moral way to do it. If grandma gets access to a federated service could I message her again?
She's not on insta just saying.
But facebook still has the power to defederate and thats the shitty thing about the fediverse in general. It's not so much about freeing the user it's more about building tribes and then walling yourself off from other tribes.
I don't like giving facebook any data at all. If you have a popular instance and you federate with facebook you are basically giving them free data.
Instead of mass defederating I would suggest all instance instead send facebook garbage data. Absolute maliciously attack threads with fake information to ruin their data sets.
Don't make it obvious at first just try to train their AI models to be retarded