Not really. Well, instance admins can defederate from it, but as a normal user you have a pitifully small list of all not easy choices. First, a couple apps like Sync and Connect can (but for them I don’t know if they would block e.g. images from there); second is move to PieFed or Mbin (I moved to PieFed myself, but could not find this post there so had to come back to my previous account, as an alt now I guess, to be able to reply here - so it’s got issues); third is move to one of only 3 tiny instances that I’ve ever heard of that have blocked it; fourth is spin up your own instance, and defederate from them. The long version.
Edit: oh, there is a basic Lemmy “instance block”, which blocks only communities on those instances - but not users, their posts, replies, votes, etc., and even that much was rolled back somewhere between 0.19.3 and 0.19.5 so that they can now send notifications to you. So it is very misleading named. The last one there is what almost caused me to leave the Fediverse entirely when I accidentally replied to one comment in ChapoTrapHouse and another somewhere in lemmygrad.ml. The replies to each kept coming in for WEEKS and WEEKS, long after I wanted it to end. The rule “remember the human” seemed to not apply to them.
There is a way to block an instance, no? Or maybe I don’t understand what you mean…
Not really. Well, instance admins can defederate from it, but as a normal user you have a pitifully small list of all not easy choices. First, a couple apps like Sync and Connect can (but for them I don’t know if they would block e.g. images from there); second is move to PieFed or Mbin (I moved to PieFed myself, but could not find this post there so had to come back to my previous account, as an alt now I guess, to be able to reply here - so it’s got issues); third is move to one of only 3 tiny instances that I’ve ever heard of that have blocked it; fourth is spin up your own instance, and defederate from them. The long version.
Edit: oh, there is a basic Lemmy “instance block”, which blocks only communities on those instances - but not users, their posts, replies, votes, etc., and even that much was rolled back somewhere between 0.19.3 and 0.19.5 so that they can now send notifications to you. So it is very misleading named. The last one there is what almost caused me to leave the Fediverse entirely when I accidentally replied to one comment in ChapoTrapHouse and another somewhere in lemmygrad.ml. The replies to each kept coming in for WEEKS and WEEKS, long after I wanted it to end. The rule “remember the human” seemed to not apply to them.