They never federated each other, so they were nice to their own in their safe spaces.
Then normal people started joining on “mainstream” instances. And both groups don’t tend to do well with an average person. Because they’ve had their echo chambers so long, they’re usually the ones complaining that Lemmy has “changed” when they venture out of their own instances.
Their safe spaces are still the same, they just want all the new instances to conform to what their Lemmy experience has been instead of just sticking to their safe space where it’s still like what they remember.