If you think it's a violation, report it. If they do nothing with it...you're out of luck.
The rules for any instance boil down to, at their most basic level, "every moderation decision is up to the people who run their instance, and there is no appeal."
It seems like fedia.io is a difference instance. You can ask lemmy.world to defederate from them. You can also block the instance yourself. Go to your settings and at the bottom block the instance.
The way I feel about it is that I don't want Lemmy to grow for growth's sake. I want people to understand how important it is to use open protocols and free software to communicate with others and that is what will lead Lemmy and other Fediverse applications to grow.