>him fighting on the battlefield for 20 years
meh, nothing manly about that
>him killing some angry cows
omg i'm so wet, you are the manliest man ever!
Dias is uneducated, not stupid. He seems to bear great emotional intelligence and is quick to understand things when he's told. His preference for a straightforward style reflects more on his nature as a person than intelligence.
While the explanation of the Oni's perspective on masculinity was simple, it does have bearing as a number of nomadic cultures throughout history do ensure that husbands who seek brides are able to provide for their future family.
My thoughts exactly. I actually like it: a nomadic culture where finding food is not easy and where potential husbands have to court the bride (or her family) with useful gifts to ask for her hand in marriage should have different values regarding what a "good catch" is like. It may feel jarring but, honestly, in hindsight, it would be weirder if they had the same ideas of romantic love we have (in general, fantasy stories are quite fantastical in that regard).
If you think about it though, managing to slaughter nearly 30 large game by one's self would be a lot more impressive than going to war. Afterall, soldiers aren't really sent off by themselves and so they always fight with at least their companions in a war. On the other hand, killing 30 beasts where each one is individually difficult to handle is a lot more impressive, especially for a nomadic tribe that places emphasis on hunting.
To quote Lynyrd Skynyrd:
"And be a simple kind of man /
Oh, be something you love and understand /
Baby be a simple kind of man /
Oh, won't you do this for me, son, if you can?"
:)
Dude probably only known mercatantes so far if he was lucky and suddenly he met a perspective to have a proper wife.
Also locals reaction is completely believable in this context.