One of problems with trying to discuss a word like anger, which has lots of meanings, is that people talk past each other, as many are doing in this discussion.
There are different kinds of anger. I have not doubt that some are useful, some are damaging, and some are both at the same time.
I think one kind of anger that can be particularly damaging is cited in the parent comment here. It's a chronic anger that was formed in childhood and accompanies a person through life looking for new threats, targets, and sources of outrage. I've known people holding that kind of anger, I've also been that person at least sometimes, and yes it's damaging to oneself and others. Profoundly maladaptive. A way to sabotage yourself, your relationships and your livelihood. That's a chronic anger.
But there are other forms of anger that might be momentary, and come up when something is going wrong that should be stopped. Maybe anger is the wrong term, but I'm talking about a sense of "this is wrong, and I'm going to intervene now." Sure, that can misfire, but it can also be useful and prevent a lot of harm.