why me, why the morning?

So all that know me know I'm not a morning person so when my commute is not smooth i tend to be moody for a while. While on the train this morning there was this woman with her 2 sons.at first i thought it was about 5 kids but soon found out i was mistaken. These two children were so loud screaming, yelling fighting the ENTIRE train ride. The whole time the mom was tuning in every now and then to YELL stop. She was so into her book that she didn't seem to have the time to or patience to deal with them. that was the LONGEST train ride in a while.
Why do parents get on public transportation and give such little attention to their children? why inconvenience others with the noise early in the morning? i work with children all day so i know its not that easy to keep children quiet but some parents don't even TRY!