No, there is not, because the question is asked in the conditional tense: notice that it starts with the words "Say you wanted ...".

It's invalid to criticize a conditional statement for the nature of its premise. A conditional statement is not a statement about the desirability or otherwise of the premise; it's a statement about the link between the premise and the conclusion (sorry, I don't really know formal logic/linguistics and those probably aren't the right terms but I do know that what I'm saying is correct.)

For the same reason, every programmer that has ever answered a "how do I" question on stackoverflow by saying "you shouldn't" is not answering the question, since the question is a shorthand for "conditional on the fact that I want to do this, what is the best way?".

There might be arrogance. It depends on what the person has in mind. If it’s someone making a time capsule purely with the hope that someone in the future might find it interesting and delightful, then no, I don’t think arrogance comes into that at all. If it’s an ancient king trying to preserve his face and memory by minting and burying coins, then maybe you could describe that ‘arrogant’, but so what, it’s still great for the people in the future who discover it and get a window into a different time.

Even trivial ephemeral records from a long time ago are incredibly useful to historians for what they give away about the time - tools, politics, morality; all are encoded inadvertently in the simplest text on any subject.

The Rosetta Stone for example is an incredibly boring text about taxes on religious organisations, but it proved to be rather useful.