Blocked instances question

Hey, I just did a quick browse through the blocked instances list for infosec.pub and have a few questions about it. Seems like we are blocking sh.itjust.works which at first glance just looks like one of the bigger general purpose instances. Meanwhile more overtly problematic instances like lemmygrad (tankie instance) or exploding heads ("free speech extremists") are federated with. Generally the block list seems fairly small compared to a lot of other instances.

So are these intentional choices or is it more a matter of the admins not (having the time to be) bothering with it? If it's not intentional, maybe checking some other instances blocklists to weed out the biggest trolls/offenders could be useful.