Blamer-Complainers can't stand the thought of being wrong. They are intolerant of imperfection, whether in themselves or others. No matter what happens and no matter where the smoking gun is found, it's never the Blamer-Complainer's fault.
Blamer-Complainers don't accept that being human sometimes means making mistakes. They are seemingly incapable of adopting the "forgive, learn, and move on" attitude. They can't accept that their thinking might be flawed, which is why they start pointing at you. Blamer-Complainers, like Bullies, are most aggressive with their most vulnerable targets.