It's also evidence that we see even today that knowledge is fragile and easily lost when it has a large tacit component. Most things technological are highly fragile because half of the knowledge required to create them is tacit.
See also: "FOG BANK".
The real bigots are the conspiracy nuts who think ancient civilizations we know of couldn't have achieved the many things we evidence of, and think it must have been aliens or other advanced civilizations on implausible magic islands.
The question is simply one of technology. We can't simply assume that people at a certain time had technology we have no evidence for, no accounts of, and no evidence of similar or near precursor technologies. The Antikythera mechanism was a shock because there was no evidence any such thing could exist at that time. We also don't have evidence such things existed in Babylon a thousand years previously, or in Egypt 3,000 years before that. Equally we have no evidence they definitely didn't have them. So should we assume they had such things? We simply make the best estimates we can and adjust when we find wonderful surprises like this one.
> The real bigots are the conspiracy nuts who think ancient civilizations we know of couldn't have achieved the many things we evidence of, and think it must have been aliens
You are not presenting any evidence that it was otherwise. I am not saying that this device was presented by aliens, but neither you are that it was not.
> So should we assume they had such things? We simply make the best estimates we can and adjust when we find wonderful surprises like this one.
We have evidence that they had it. How they had it is a separate question.
I assume the next "civilization" might not be able to figure out how/what out machines are doing and they would have a similar discussion.
As I explained very carefully, this has nothing to do with them being smart or dumb. We already know they were very smart from their written records. I explained how we know that. They just didn’t have our technology. It turns out they had more technology than we previously suspected, that’s all.
> You are not presenting any evidence that it was otherwise.
It’s not possible to prove a negative. The only route to reasonably reliable knowledge is following the evidence and preferring the simplest explanations for things.
If I have to provide evidence it wasn’t aliens to doubt that explanation, do I also have to provide evidence it wasn’t Atlanteans, and evidence that it wasn’t time travelers, and evidence that it wasn’t extra dimensional beings? If I can’t provide that evidence what do we conclude, that it was probably alien time travelling extradimensional beings from Atlantis?