Typically, if you see that one person is being banned from a bunch of communities at the same time, it just means that they are being banned from the instance.

If an admin wants to ban one of their own users, it's a single activity that's federated out, but if they want to ban a remote user, the only way it can be done under the current system is for every community that the banned person has interacted with to ban them. It's an automatic process, triggered by the admin pressing one button once. (it's not a perfect solution, because nothing prevents the banned user interacting with other communities, at least as far as their local instance is concerned).

Because that's the Admin of lemmy.blahaj.zone. Probably doing Admin stuff like cleaning up, enforcing instance rules... Doing the instance-wide userbans. Other instances have some Automod bot for that. In this case it seems to be done from the Admin account. And that's most of the rows in your screenshot. There is some technical shortcoming in Lemmy. And that's why admins do it this way and it produces lots of entries instead of just one line in the modlog.

Edit: Ada explained in the previous post here, the one they discuss (half your screenshot) is an instance-ban, that automatically issues community bans

Instance bans automatically issue community bans to all local communities a user has been active in

She's the instance admin. Technically, she moderates everything site wide.