This is an interesting argument because I run into this question all the time. My answer is simple: Yes we should. Homework in general is a great way of teaching students how to be responsible and do what they should. It is true that it is important to spend time with family/friends but, as far as I know, most schools in the US let out around 2:30-3:00 roughly, so they have the rest of the day to do whatever. Homework in general doesn't usually take that long either. Homework should roughly take about 1 hour up to 5 hours maximum at the high school level. So it isn't as bad.