Is it wrong to get into an argument with anyone else on the board?
So, she was a jerk, but people should have ignored it because of perceived benefit. But you won't ignore the people who called her out on it because they don't carry the same perceived benefit.
You're using a sliding scale of what's right/wrong to do based on what you feel is beneficial to you. That's called being a "respecter of persons", and many would consider that hypocritical.
In other words, it's putting your integrity up for bid.
Machiavelli taught that right/wrong are defined by outcome. i.e. "The ends justify the means." Today, "Machiavellian" is generally used as a pejorative.