The police have to respond all calls for help and without determining that the accused was actually violent or not, they need to make the arrest. Most of the time police arrest both the victim and the accused so as to investigate later about the situation created. This law is all about women empowerment as the abusers think twice before being violent. They know that one phone call would be enough to put them behind the bars. In misdemeanor cases, the mandatory arrests have lowered the rate of violence. Those who were punished were least likely to abuse again.
But negativity comes with positivity. According to long research history, the individuals whose partners were arrested for abusing them, died earlier than other victims of violence whose partners were not arrested. Such individuals either live very poor life or become heart or cancer patients later on. The feeling of guilt can also depress them and affect their mental health also.
There are has been another criticism on mandatory arrest laws that such arrests do not leave any option for the partners to decide about their future themselves. It is more like a last resort for any