https://www.cam.ac.uk/research/news/mandatory-arrest-in-domestic-violence-call-outs-causes-early-death-in-victims

Aside from giving a green light to making false allegations, and treating men as guilty until proven innocent, a principle of mandatory arrest also reduces the life expectancy of the complainant. There really is no reason to blanket arrest all men (or women) when accused of domestic violence, as happens currently in the UK and USA for men, but never women.