I'm not the parent and I don't have any kids, so this is just based on what I observe.
There's this mother who, when her daughter (about 3 years old) starts crying and making a fuss, she'll lose her patience and try to "out scream" or "out annoy" her. In other words, she starts crying and screaming, and the mother will tell the child, "I can scream louder!!!!!!!!! AH!!!!!!!!!!!!!!!!!!!!!!!!!" and give those sort of responses, basically over-yelling, etc., as if it's some sort of dominating display attempt to teach the kid (e.g., "I'm the parent and I can scream louder and I'm in control!!!!!!").
From what I notice, the child will keep crying and having a tantrum, and eventually the mother will completely neglect/ignore her by scaring her and yelling at her to stay in her room and will tell the daughter that she'll refuse to listen to her or get her anything unless she "shuts up" and stops crying. My assumption is the child stops crying when she's physically exhausted from it; not because she learned anything from the method. In short, the behavior doesn't change and it's not something I like being around.
What happens next is the daughter keeps screaming, crying, etc., and as the duration increases, the mother will occasionally enter the room and continue screaming very loudly and angrily at her, near to the point where it's heard houses away.
My question is, is this damaging/unproductive in raising a kid? Is trying to "defeat" your children harmful by trying to illustrate to them that you're, say, louder, can yell louder, can be more annoying, can pull harder (in, say, a tantrum when the child is yanking stuff) or even throw stuff after the kids do it to try and "teach them" it's wrong by doing the same thing to a greater extent.
For another example, a child has a tantrum and starts breaking stuff, and the parent gets explosively angry and starts screaming and breaking stuff in a more vicious manner.
What are the consequences of this, and how would this affect kids? More importantly, is this bad 100%?