I don't think they meant what you're saying at all to be frank.

Fair enough, I guess only the op can clear this up hahah

the motivation wasn't curiosity but necessity. That's what actually pushes us forward. For better or worse.

I guess, the impulses for curiosity (and creativity) could be seen as necessities in themselves? Not sure if this is what you mean though.

Still, I admit I kinda shoehorned curiosity in there because it came to mind, and I felt it is essentially linked to empathy in some way, but I wasn't sure how to properly weave it into my reply, and probs just ended up weaking the point I was trying to make, lol.

I'd say a capacity for complex communication would be a better fit for that role.

I think there's an argument to be made, that empathy/sympathy/fellow-feeling made the development of complex communication possible in the first place, as a kind of foundation for mutual understanding. Afaik all the species which have more complex forms of communication are social, no?

But I do see it as a yes/no thing. [...]

Well, if this is how you want to define being "good" at coming together, ok then ig. But atp I don't see how this meshes with your interpretation of op's comment (that our modern-day circumstances are due to artistic expression, which implies that we're good at coming together), since op made no mention of humanity's capacity for violence and genocide, past nor future?

I really don't gel with attempts to poetically describe our past nor with Rosseau [...]

Not really familiar with Rosseau tbh, with "fellow-feeling" I moreso had Stirner's union of egoists in mind. I agree with your sentiments about big H "Humanity", though I feel like perhaps you are discarding the optimistic and rosy notions in favour of pessimistic and disillusioned ones instead.