I mean, you have a point, of course, but the aim of these digital terrorists is precisely to take Lemmy down. These attacks are happening across many different instances and the long-term solution cannot just be to give up.
But if all the instances work together on a federated solution, we might have a chance to keep Lemmy alive long enough that a) this sort of thing will naturally die down, and b) the collective efforts will allow bad actors to be identified and stopped no matter where they're coming from.