I think they do know it, and god I hope Cas gets called to the carpet over it. How could they NOT know?

But also ... it's weird. I feel like the writers have been paying too much attention to what some of the fandom rhetoric is, and tiptoeing through AO3 to see what's trending, then using that stuff to pad episodes. And they don't have a good understanding of fandom, to be honest. So this is what we get.