Okay now I get it and apologies Sir @janton.
It's all about honor isn't it.
And the honor statement is to fight to the death if need be.
No surrender and no absconding, only to the bitter end.
Imagine a thousand strong Impi armed only with spears attacking 200 guys with rifles. When you do the math, it's a slaughter.
But yes, that's their fighting style.

Have you seen this;

https://en.wikipedia.org/wiki/Battle_of_Blood_River