Life is full of pain and unpleasantries but choosing to act as if they don't exist is naive. It's like having a recurring massive pain on your head but neglecting to inform your doctor during a check up. Ignoring a problem does not make it better but usually ends up making it worse. This is especially damaging for children because despite a parent denying the ugly, it still comes out in some fashion. Children are forming their impression of the world and when they have no explanation for why mommy is being a bitch, there is a good chance that they will appropriate the blame. I've heard many stories of adult children talking to their aged parents who finally break the silence. Understanding the why behind their parents actions can be life changing.
I am not advocating every exchange be a vulgar, profanity laced diatribe; however, trying to ameliorate life in your mind by placing things off limits does everyone a disservice. Some people call themselves realists but usually that translates to "I don't delude myself but only see the negative" which isn't healthy either. We don't need to be more sensitive as a society, just more honest; accepting the reality of life as inevitable while relishing the gift we have been given.