Because it has always been this way. He never thought to question it, and he never would. He never thought it was strange how he and Knuckle became friends, and then how that runt and Sasagawa Ryohei became friends. Alaude never questioned it, despite it being strange, uncanny, unnatural.
No. He never thought it was strange. He just assumed that it was something to show the similarity between the Primo generation and the Decimo generation. After all, the resemblance between both was uncanny, to the extent of some nationalities even being the same. He didn't really want to question this. It would sound like he was question his friendship with Knuckle.
He didn't want to do that. He couldn't question it. They were... best friends. And they always would be.
Even if a chasm separated them, and one plummeted. Even if one broke down and one flew away. Even if they were sent to different parts of the world.
They would still be best friends.
Knuckle always questioned why.
Alaude always replied, because it is how it is.