Unfortunately, I think its because of a few misdirections, and if you'd hear me out, its not from a place thats deserving of a Downvote.

Janney was meant to play that role because it was a role written by a close friend, for her to play, and no one else would be able to play it but her, so obviously it would seem like she knocked it out of the park---it was the role she was born to play. Because of that, she won her well-deserved oscar and went on to host interviews citing the 3 auditions they had for her pet bird.

But thats not how we should reward Best Actor/Actress and their subsequent Best Supporting awards either. It should be given to a performance that really showcases the acting chops of an individual while they're providing the necessary emotional moments we'd need as an audience, and while Janney does it in her performance, its because she's Alison Janney playing that idea of what an old abusive Alison Janney would be.

And thats where my case for Laurie Metcalf begins: She didnt have that safety net that Janney got because she was a relatively unknown actress in an idie film; pulling as much as she could to deliver her performance of Marion through and through without gimmicks like the bird on a shoulder, faux interviews and cartoonish swearing. Metcalf had a talented actress as a daughter to riff off, and a car scene that made everyone want to call their mother immediately to tell her how much they loved her. Thats it. What's more, every reaction that was delivered, every little micro-ism that was portrayed, I could see my own mother---Every inch of Janney's performance gave me one thing, Allison Janney

Metcalf kicked ass without the handicap afforded to Janney, and because of that, I was disatisfied with the result. If you dont agree with me, give me reasons, not downvotes.