Despite running the same code and (generally) being able to see each others' posts, different Lemmy instances (or as you called them, versions) are not run by the same people, so often have different rules as to what is and isn't allowed on their instance. Some instances are very lenient, allowing anything that isn't outright illegal in their country of hosting to be posted, while another instance might have far stricter rules, disallowing things like nudity or vocalising certain political views, banning users on their instance who post such content and defederating other instances (effectively pretending the defederated instance doesn't exist and refusing to view any content posted from there) where such content is prolific.
Peekystar
Okay, but what if some billionaire bought all the issues? Would that leave us with no issues because the billionaire paid to have them offloaded onto them, or low-quality issues because the billionaire now hogs all the premium paid issues?
Oh, no no no, this is actually just a plane shedding its skin, like a snake. In actuality, humans just fly around in the shed skin; you wouldn't believe the industrial plane farms we have to encourage the shedding of skin we can use.
I've started encountering the ad-blocker blocker myself over the past few days, but fortunately it proves to be terrible at its job in my experience, as a small X allows it to be dismissed after 3 or 5 seconds, which is outright better than waiting for the 5 seconds plus load time of a skippable ad, or the many more seconds of an unskippable ad or two. This might be useful for me if they ever decide to remove the ability to dismiss the ad-blocker blocker, though.
Ancestors, since they'd be far more likely rationalise my bizarre present-day manner as being possessed by demons or something to that effect rather than assuming I'm from half a millennium in the future, I can't say I have any specific guesses as to what the society of 2523 might look like, but I suspect that they'd be far more likely to jump to the somewhat improbable sci-fi explanation of time travel (or perhaps some other technological explanation like mind malware if brain implants become a thing) than assuming supernatural explanations of demons or witchcraft.