it does basically boil down to what other people have said but I'll elaborate.
The reasons are political disagreements from the admins of lemmy.world, and them taking the site's zealous left-wing opinions and shitposting culture as prima-facie evidence that hexbear users cannot be trusted not to break lemmy.world rules (unstated which rules) by pushing "their beliefs and ideology". It almost sounds reasonable until you think about it like, at all. It's an explicitly political instance (though honestly >50% of the posting is just news of the day and banter), so of course the users will by and large have those political opinions and post them. As long as they do so within the rules of lemmy.world I don't see the issue personally.
https://lemmon.zerobytes.monster/index
it's not just you, the stats bear it out. LW has the worst uptime of any major instance. 92% so far this month according to their own monitoring and worse on bad days. They see a lot of load and have not scaled up enough to resolve it, nor have they restricted user signups at all to spread out new users across the lemmyverse. Seems like a very growth oriented mindset, which I don't love to see spreading to the fediverse.