No one is saying that that there was criminal culpability. No one is saying that there was one mens rea plotting the deaths of thousands of Haitians.
Nevertheless, there is overwhelming evidence that the UN contingent to Haiti from Nepal introduced a very distinctive and virulent strain of cholera - this in Haiti which had seen not one case of cholera for over 100 years. This caused the deaths of thousands of Haitians.
No-one is saying that anyone is criminally guilty - least of all the Nepalese troops. But why were the Nepalese housed in primitive, unsanitary camps? The money to provide them with proper facilities - where did that go?
BBC News - Haiti cholera epidemic 'most likely' started at UN camp - top scientist