@Jerry thanks for your watching mstdn.jp actually.
Yes, blocking is reasonable. It is because mstdn.jp didn’t moderate.
Mstdn.jp is world 10th biggest server. Many admins may check if mstdn.jp is federate-able server or not, and decided to block.
And more many admins don’t check by themselves and block with pasting lists.
I’m willing to support mstdn.jp back if they start to moderate. But they won’t.