Long story short, they don’t have the mod capacity to micromanage evry single comment, since unless you defederate, you have to moderate every comment and post that gets seen by your instance, so the whole fediverse basically, and they just can’t do that.
Some instances have attracted some toxic behaviors and federating with them added an influx of comments that weren’t in line with their rules.
They decided to defederate all the big instances that didn’t filter sing ups.
It’s a blanket solution, and honestly, I don’t blame them for it, lemmy moderation is a bit hell.
Their rules are a bit strict, but I approve of what they are trying to do, creating a “safe” space… The rest of the fediverse is a bit of a far-west with anything goes being the rule…
Regardless of if it’s on the visual spectrum or not, it’s all called light as long as it’s electromagnetic radiations
Radio waves are light, gamma rays are light, gravitational waves are not, sound waves are not