The size of all involved instances grows since they all store a copy.
if Lemmy1 and Lemmy3 aren’t subscribed to each other, but they both comment on a thread on Lemmy2, will they see each other’s comments?
Yes, when lemmy2 receives a comment from an outside instance it will then send that comment to all subscribed instances.
No absolutely not wtf
The people getting ICE’d are also people who don’t deserve to go to concentration camps just because you don’t like them