[They are stubborn. They're very stubborn, especially when it comes to adults. But Marco's explanation at least has him thinking on it a little. He's...one of the Fourth God's friends. One of his adult friends. And he'd be embarrassed if he had to tell him that he lost his card. That's not like adults, usually. But...unfortunately for Marco, he has someone he doesn't want to disappoint. So it's important to keep the card.

However, that's not something he's going to tell him. Actually, he's going to zero in on something the other man said.]

...it's not the right thing. He's trying to kill monsters. He's trying to kill Shingetsu-kun. And it's not his fault he's a monster. So why does he have to be hurt for it?

[It just reeks of what the adults back home did. It wasn't their fault that they acted the way they did, but instead of trying to help them, the adults just labeled them as problems and punished them. Child or not, what he's doing isn't right.]