@JamesGleick
For many it's far better to communicate inside one social medium, even a "closed" one, than to deal with the hassle of what can and can not be said on one instance in the #Fediverse or another, blockwars being one result of such "decentralisation".
To many #Threads may be the right thing to escape the negative effects of #federation.
That you don't understand why some ask to follow them over to Threads may be due to a lack of technical understanding of federation.