I just don't understand kids today

I sure sound old when I write that, don't I?  I just truly don't understand kids today though.  The Ag class that I'm in has very challenging afternoon classes.  We made it through the first group pretty fine.  The second group is the one that has always been challenging and can do a real number on my nerves.  Today, I actually had a student take a phone call in the middle of class.  Now I recognize that we might be the ONLY family that doesn't allow our children to take phones to school.  There have been some times it would've been nice, but about 99% of the time it isn't necessary and my children don't need one more distraction.  If the child had come to me and said I received a text and need to make an emergency phone call, I would've certainly accommodated the need.  However, when I told the child to step into the hallway, he began to argue with me and continued to argue even after hanging up.  I finally just sent him to the principal.  I just don't understand these children who feel they are so entitled to do whatever they want, and then actually have the nerve and audacity to disagree with me when I tell them it's not okay.  It is actually astounding to me in fact.  I would never have thought to speak to an adult the way many kids speak to me every day.  I recognize that it is late in the day on a Friday, and we are late in the school year so no one is on their best behavior at this point.  At the same time, if I ever find out my children behaved the way some of these kids do, I would absolutely come unglued.  I don't want to be judgmental about other parents because I absolutely understand the difficulty in raising teens.  However, I also know kindness and respect has to be modeled and taught at home before the teachers at school can do anything at all!