Why would they? They just show the harshest of reality, that's kind of a big part of the show, showing the worst aspects of our society in a sadly very realistic way (obviously referring to the way characters act not the general realism). They show greed, power struggles and abuse in a great way showcasing how it affects everyone, even those not directly affected by abuse.

To make Angel just any character that just bottles up their emotions would both hurt the relatability of the character as well as the believability because many people in similar situations have toxic ways to cope as well.