It's been a very long time since he's gotten drunk, and after having many times where he's lost control thanks to Justice, Anders isn't really sure he wants to lose control again. Sober isn't a great state for this, but it's better.

"I... I am." He started placing rocks around the fire and rinsing them off with fast-melting ice so the meat can be cooked on them. "I wasn't in a good place, I was possessed, and I made a poor decision. A stupid, desperate decision, after several friends had been killed and the Circle was about to be slaughtered."

While Anders can't defend the decision, it hadn't happened in isolation.