Honestly it reads as naivete. That they believe that defederating is the worst that Meta would, and the rest of the instances would simply go back to a state of pre-Meta. This seems like an illogical conclusion, as any activity will fundamentally change the landscape in which they dwell.

Meta doesn't need to defederate to cause harm to the network they are seeking access to, in fact the opposite seems more likely. Having a presence within the landscape, especially with such a powerful footprint, will have a significant impact on the medium as a whole.