We are only a little removed from our 'wild west' days and too many people still see physical confrontation as a viable way to resolve issues. Sometimes we recognize it for 'bullying', other times as 'domestic violence', but too often it is just labeled as 'boys being boys' or 'just a fight' ' or 'justified reaction to ____', or an 'unfortunate tipping point' or 'too much alcohol'.
Violence is just bad and unfortunately the fact these too reached this point in what has been apparently a very important relationship for them both is not a good omen for either, nor for their current relationship. It was 'just a fight' but it was physical and it was between domestic partners. If one had been 'weaker' it might actually have been less violent, quickly over, and never brought to public light. But then one of them would have the bruises, and over time likely had bruises on top of bruises in a more classic cycle of abuse.