Nudge
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Do homins have hands?
Do homins have noses?
Would it be instinctual for homins to cover their noses at bad smells?
Finally, from the lore perspective, are homins intellectually stunted?
That is, are the homins lack the intellectual capacity to come up with new things?
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Let's not make homins idiots.
This is dangerous argumentation, because it can cover anything you can imagine OCC. Remember that homins are not humans and the "homin evolution in time" was not as same as humans'.
Ok, lets think in roleplay. Are homins thinking the way you (human) do? What are their goals and visions? Where are those inventors who should invent things? Is it you?
If anything, by all fights around I think its more possible that homins will invent new weapons more than gas masks :(