The reason for this is that she's made it quite clear that she sees most forms of violence as being wonderfully funny because they don't really matter. The woman was raised to believe that certain targets of violence either deserve it and that when violence happens to other categories of people or animals, it can't be said to really hurt and thanks to the miracle of the confirmation bias, nothing has happened to change her mind all that much. Watching Farley get abused is loads of fun because dogs are just big, furry clowns here to amuse us, children beating the crap out of one another are funny because nothing that happens before you're eighteen counts and watching weak little women like Liz and Elly pretend like they can hurt big, strong men is fun because, well, female-on-male violence is harmless. The only form of violence that counts is one she only depicted the once: male-on-female abuse. That is not funny because someone who shouldn't be hurt got hurt. War is bad merely because of its potential to hurt mothers and children, school yard beefs are bad because they scare helpless girls and all sports fans are monsters who bash up women; her mother said so so it must be true.
The problem of trying to explain to her that female-on-male violence or kicking a dog that bothers her are as bad as male-on-female violence has a lot to do with her reluctance to question any of the moral precepts she was raised to respect that aren't an inconvenience to her. It's like trying to get Liz to see that while she might find it unfair that she can't see a married man whenever she wants to, common sense and common courtesy bar the door for her.