There's a lot to unpack here. For the sake of convenience, I'm going to assume that what Luminous said was a legitimate call for violence and was therefore not complying with the Lemmy.world code of conduct.

If we assume that, then the Lemmy.world terms say that they can:

• remove the content and ask a user not to do it again, and/or,
• (if it's a second time) suspend the account temporarily, and/or,
• restrict or banish the community, and/or,
• remove all of that user's content, and/or,
• permanently ban the user.

I have no idea how many of those had already happened, I'm going to assume for convenience again that some of it did. The site bylaws also say that for community bans and content removal:

• Bans "should only be used as a last resort for hostile users OR for users that are known bad faith actors."
• "Any community user ban CAN and SHOULD have a clearly documented reason pointing to explicit rules broken."
• "any content that they DO remove, they should ideally be able to cite the community rules that were broken."

I note that all of Luminous' content was removed, and while the "Our Rights" section says this can happen, it somewhat contrasts with the guidelines for documenting content removal. But there's still nothing in any of this that suggests defederating from the entire instance is warranted or an appropriate course of action. If community bans are considered a last resort, then it seems logical that defederating has at the bare minimum the same threshold of seriousness.

Let's assume for convenience again that the comments from one admin can be sufficient cause for defederation, and its absence from the ToS is an oversight. If that's the case, then the bylaws and prior defederation examples (eg. lemmygrad) suggest that this should be adequately explained. But that didn't happen, and it's not clear whether the other admins were involved in the decision.

Even if all of the above reactions to Luminous' comment were justified and proper, the actions afterwards by lemmy.world admins / mods don't inspire my confidence. I can see there has been:

• This refederation announcement, only posted as a regular post (I found it yesterday by chance). It only briefly outlines the events leading up to this.
• One user in this thread has been temporarily community banned for "Spam, harassment" after three removed posts in the thread, which doesn't seem like spam quantity. Two of those posts cite the reason "this isn't about jordanlund", yet further down in the thread, an admin is litigating the jordanlund situation. Other far more off topic content is in this thread, so if that is a concern, it's not clear why the other comments remain.
• A few users have been permanently(?) banned from the instance with the reasons "troll" or "calling FHF members nazis". It's unclear whether the removed comments or user histories rose to the level of needing an instance ban.
• Multiple other users have been temporarily banned from this community for reasons spanning from "uncivil" to "disinformation", to "sealioning and harassment". Many of the removed comments from those users did not seem to meet those descriptions either.
• Many other removed comments from non-banned users, with varying levels of clear rules broken.
• One moderator indicating the defederation mostly only targets several "loud" people and the instance size is only 165 people, which undercuts both the reasoning for why defederation was necessary and the justification for including 150 users as collateral (along with anyone who may have wanted to interact with them). Several people can be dealt with using individual bans, and that quantity are unlikely to be negatively impacting lemmy.world at scale.
• No response from the only person further up the leadership ladder for whether / how Lemmy.world admin are evaluating the original decisions, governance process for defederation, or the bus factor and risks of one person being site admin and top moderator and infra simultaneously. Not even a "I'm alive and considering the issue" acknowledgement, unless done behind the cover of the lwadmin account.
• Lots of little bits of engagement otherwise from Lemmy.world admin or mods with various tangents in the thread.

Very little here seems to align with the by laws and expectations for proportionate community moderator conduct.

The situation looks to me like it has been poorly handled, and there is no sign of any compromise or admission that any of the events that up to now could have been handled differently, or a process for how it might be handled in the future. I just don't see much in the way of community building or good will, but I do see the same patterns that have inspired other lemmy.world drama over the years.

If one admin's comments or actions aren't sufficient for justifying defederation, then it's unclear why dbzer0 is being considered for defederation at all. But, if one admin's comments or actions are sufficient justification, then the situation in this thread opens the door for other instances to defederate from Lemmy.world.