wondering what the future ethical transhuman civilization would do and think about all that feels totally appropriate to me. It's exactly what I would expect of Harry, the one who (re-)invented True Patronus.

I concede this. I think I just don't like this part of Harry that much, but that is not the same as saying it's not in character.

The rest of my point remains, that after all all the pressure built up in the previous 8 chapters, this one is too relaxed and lacking in precautionary thinking.

It's fine from a pure story-telling point of view, because we can assume Harry knows more about it than we do (he's living in it after all, he did read many books about magic, do many experiments, attend to lessons, ...) but it's not fair to ask us to outguess such things.

Is it really fine from a storytelling point of view? I suggest that correct storytelling means making solution-relevant rules clear in advance. Like in Death Note, the plot often hinges on how exactly the notebooks work, but these rules - and how much each character knows about them - are made very clear before they become pivotal.

And clearly EY tried to do this, and came close (with the robust-wand thing). I just don't think it quite worked.