There is a lot to unpack here, but first and foremost, your statement contains numerous inaccuracies - e.g. it's not merely one user it is an admin - but also I notice it contains numerous instances of inflammatory language, e.g. "Trying to hurt a whole instance and the whole federation concept". AN can feel absolutely free to do whatever it pleases, so why shouldn't LW have the same rights, to block calls for literal and actual irl murder levied in their direction? Also, this is hardly the first time that one instance has defederated from another instance - this tiny blip won't even be noticed by the vast majority of people on LW.

But if you do want to talk about "hurting" someone, I find myself hard pressed to think about a worse fate than to be literally and actually irl murdered, genocided by someone who feels no remorse at all about killing off your entire family, just so that you will suffer?

And you are not even on LW, nor AN - this will not impact you personally in the slightest?

doesn’t matter which instance you land on when you sign in

Please stop spreading this. Whoever said this was incorrect. As you yourself claim, it matters a great deal to pick an instance. So pick one that aligns with your values, so that the moderation practices are those that you can live with. Otherwise, pick a different instance - such as lemmy.dbzer0.com - that you may prefer better. Also, people did not migrate away from Lemm.ee due to its restrictive moderation practices - so if you were claiming this then that would be disinformation. Although it is a strong argument that its LENIENT moderation practices were what led to its downfall, where zero admins across the entirety of all the billions of people on planet Earth could be found that were willing to put up with all the crap spewn in their direction. But this stance only weakens your own argument further, claiming that now LW should do the same as lemm.ee, and thereby end up with the same result?

If you want to do whatever you want, then start your own instance. The LW admins did precisely that, and they do not appreciate having calls for their murder put out by AN. It is their right to defederate from them if they please.

Also, we are still here. Anyone at any time may go to Reddit or X or Bluesky if they prefer, but we will remain. That is our choice. Speaking of choices, where is your acknowledgement of the other side of this - you are chiding the LW admin team, but why not (also?) chide those of AN, who routinely call for murder of people in Western civilizations? If anyone is "fragmenting the Threadiverse", don't you think that calls for actual, physical irl murder might be at least partway a cause for such a fragmentation effect? The LW team did not take this action lightly nor did it come out of nowhere - AN was the one that started this? And now LW has to determine its own response in turn.