It turns out in the last episode that the rapist wife beating guy was actively beating his wife in front of a group of women and one of those women pushed him and he happened to fall down the stairs and die. Then for some reason instead of telling the truth, the women (including a lawyer) decide it is better and more empowering to lie to the cops?

There is no reason to cover up what they did. They committed no crime leading up to his death, but committed multiple crimes covering it up. If they would have gotten together and decided to murder him in cold blood and cover it up maybe it would work. But they accidentally killed him while he was in the middle of physically assaulting his wife.

If there is a single plausible explanation for why they lied to the cops, I'd love to hear it. The entire framing device of the show was worthless.