Ok, so let me try and answer this a different way. There's been a lot of discussions so far and it's not really gone well.
Flags are a way of users raising concerns about questions, answers, or comments that need to be brought to the attention of the moderators. We look at the flags, look at the content and do whatever needs doing. Most of the time, it's clear.
Very rarely, we get contentious posts that create an extraordinary amount of negative attention. Sometimes in the form of comments, sometimes flags.
In this case, 18 flags were raised by people in the community, all of them expressing concerns about the answer, there were many other comments. There is no minimum or maximum number of flags before we consider deleting a post - we look at each one in context. However, 18 flags means that people are really, really concerned about something.
The post in question advised people that the only form of abuse that people should intervene with is when a man hits a woman - by implication people are advised to stand by and allow all other kinds of abuse, regardless of whether it's physical, emotional, or between any differentiations (or lack of differentiation). It's ok to stand by and let someone abuse someone else because it's not a man hitting a woman.
One of the core statements of the Code of Conduct that everyone agrees to in participating in this community is to not abuse or condone abuse in any fashion.
This answer goes against that by limiting intervention to only one form of abuse. Many comments were raised, but the answer wasn't clarified in any way.
In order to stop the situation from snowballing further, the answer was deleted.
We don't do this lightly, having to delete stuff is only done after a lot of consideration, and taking on board the feelings of the community, who were clearly made uncomfortable with this answer.