In Tammy's version, she's a ghost: She died, she was resurrected, she lives here now. (Daniel's and Clarice's versions of Apotheosis agree on this, but they're all three wrong.) She has no other logical option than to assume that Zoë is the same thing, which is more than enough reason for vengeance. She has no context for Zoë's continuity -- born, died a few months later, got here by another route -- because the concept of Our Zoë is something nobody on the show can really get their heads around, because she is a miracle. The only evidence for, the anomalous Deathwalker thing, just makes Tammy's continuity more complete. Our continuity wants nothing more than to connect itself to itself, because that's the meaning of the word but also the only way we can live.
And knowing this fact about humans means a lot of power, for good or ill. For example, right now kidnapped Lacy is having her sense of continuity ripped apart, quite purposefully, by sexy Nestor: First the screaming abuses -- "You're useless! Worthless! "I don't even know why Clarice wants you here!" -- and then the sexy embraces, the protective muscles, curling around her up in the Willow attic: "Shh, it's okay. I won't let the others hurt you." Back and forth, good cop/bad cop, drugs in the water, and Lacy getting the floor ripped out from under her every time she finds a place to stand. Devastating.
Or in business: You've got Tomas Vergis standing there in the middle of a board meeting, for the company he won fair and square, that he didn't ask for. Cyrus (gleefully-ish) explains to him that it's an emergency meeting about reinstating Daniel as the head of their company, and suddenly none of his boardmembers can even look him in the eye. Cyrus herds him out and tells him they'll let him know what they decide. And over in the Graystone house, a lifetime victim of continuity error waits for the call, with nowhere to stand, with his whole world in the box like a cat, neither alive nor dead. So when Cyrus finally lets him know the unanimous vote is in, he crumples like a puppet with its strings cut. Back on the ground again, with nothing to lose.
The Willow wives, particularly the pregnant one Mar-Beth, are not feeling this latest outrage. Clarice has been off in her Kooky Kabin for weeks and weeks, and suddenly she's back with this jailbait torture victim in the attic. Not what she signed on for. And you know Clarice, she's like, "Why am I living at that cabin? God. Why did I kidnap a little girl? God." I mean, I can't imagine there was a time Clarice wasn't like this, so I'm not sure what Mar-Beth thought she was getting into, but the fact that the husbands seem to be mostly on Team Clarice makes me think it's partially due to her weird sex powers, and if that's a problem for you, don't marry Clarice Willow. She's got like three magic powers, and the other two have to do with getting real before you know what hit you.