Do Hobgoblins realize that they were only created as a weapon against elves?
It would also mean that they accept the fact that they were probably created by arcane magic.
Do they deny it? Or do they pragmatically accept it?
They are what they are and they do what they do because whoever is in charge says so. You could create a Hobgoblin character who has some kind of breakdown/epiphany regarding his species' origins, but Hobgoblin society as a whole probably won't care.
I homebrew my hobgoblins anyway, so the Golarion version doesn't really come into play for me.
I'm running a campaign where all the PCs are hobgoblins, and they know that they were created by arcane magic and they emphasize that the first thing hobgoblins did after coming into existence was to kill the wizard that created them.