If terrorists and pedophiles aren't using your encrypted service, that means it doesn't work. Something similar could be said about federation.
Oh dear. After 6 years this is what you call a 'Twitter alternative'. At this point it is not only a fringe alternative it is basically competing against Gab, and even then, it is still losing against that.
This is a failure and it is not early days.
On the other hand, the fact that it's still around after 6 years suggests it has a niche. It's never going to beat centralized services, but it would be kind of ridiculous to expect it to.
This is an old article but I don't see the point in calling out Japanese instances for cartoons when American Nazis and actual child molesters are on the network as well. I find lolicon gross, but if you're going to look for something to worry about on a decentralized, federated, censorship resistant network like Mastrodon, you can find much worse.