Why so much trash talking?

I can not believe it, as I sat down on a typical night to play Gears of War, I faced myself with a few teens, maybe even pre-teens that were talking so much trash.  Where are the parents and how can they say such things. I guess this is pretty typical over xbox and I should of been used to it since I have been on XBL for the past 3 years.  But then again, I am not use to it.  Oh well, maybe I am over reacting some, but when my daughter is sitting next to me watching me play and can hear what they are saying, and she wonders why I won't let her play games online over XBL.