For the record I have never been kicked from a dungeon. Although I completely understand it does happen, and not always fairly.
However, I have had to go afk for 5 minutes or more in dungeons on a number of occasions. One time my mother was going out of town and had to stop by sooner than anticipated. Another time I got an important phone call for a job. My companion animals often need attention during my dungeons, such as let in/outside. I've also had to tend to food quickly while in a dungeon due to my significant other being occupied with an important call. People's lives don't just stop because they are playing a game that may require their near full attention. Nor should the rest of the team be expected to wait and accommodate a player with a busy life. Of course people should put the appropriate amount of time aside in order to run a dungeon. But on the same note, why not give patient and understanding players the choice to allow people the time they may need during a dungeon?