Here's the description by both:
sh.itjust.works:
A bilingual (EN/FR) general-purpose instance located in eastern Canada! Powered by 99% renewable energy! Everyone is welcome eh.
Lemmy.World:
A generic Lemmy server for everyone to use. (...) Lemmy.World is a general-purpose Lemmy instance of various topics, for the entire world to use
The comments about instances being "good" or "bad" is just plain ol' tribalism.
Users get attacked for the instances they registered to, even if they were unaware of instance politics when they actually registered. That sucks!