You find this surprising? It's obvious by their actions that we're not much more than symbols of property to them. They have no obligation to tell us anything.

[Hi Drift, it's your favorite Cybertronian.]

[Oof. And he's feeling extra cynical today!]

[He'd normally doubt the existence of zombies(especially considering who it was coming from), but considering everything he had seen here, he's willing to take give him the benefit of the doubt.]

I agree that this must be investigated.