A) How many actually good examples do we have to draw upon? Most such things are pretty blatant attempts at saving face. This at least has some sincerity to it.
B) He isn't justifying, excusing or denying. He did quit drinking already, which is perhaps the most important thing he could do to prove he is taking it seriously that he needs to stop hurting other people. He is fairly realistic that being better in the future is the primary thing he can do. He also acknowledges that it doesn't undo his past actions or somehow make things okay for people he hurt.
Amends are really hard to do. They also don't always come in a form readily recognizable as directly related to the bad act.
Also, he kept it short and didn't make it about him and his big feels or sob story. It is reasonably gracious in that regard.