It is a combination. On one hand, you have Dredd's opening instruction to Anderson:
Judge Dredd: Twelve serious crimes reported every minute. Seventeen thousand per day. We can respond to around six percent.
Anderson: Which six percent?
Judge Dredd: Your show, rookie. You tell me.
So, they live in a world where violent crime is rampant, and the authorities can only deal with a fraction of them.
The Chief Judge expressed a desire to test Anderson by throwing her in the deep end:
Chief Judge: Sink or swim. Chuck her in the deep end.
Judge Dredd: It's all the deep end.
So Dredd obviously recognizes that Megacity One is extremely dangerous.
When explaining to the Chief Judge what happened in Peachtrees, Dredd's response is extremely understated.
Judge Dredd: The perps were uncooperative.
Even by Dredd's standards, this is an understatement. It reminds me of soldiers who have seen battle. They almost never talk about it. And even more rarely talk about it to non-soldiers. I think Dredd recognized that Anderson has what it takes to be a Judge, and what they went through is something not to be shared outside the circle of those that lived through it.
What Dredd said was factually true. The Chief Judge could see that there was more to it. BY not talking about the details, Dredd was showing camaraderie to Anderson.