For those of us educated in good middle class schools, these may seem like trivial things. My sister teaches in an all-black school and experiences the reality every day. Tardiness and dress code violations are not trivial...they are all about disrupting the class and getting respect from other low-life thugs. They don't quietly enter the classroom late and meekly take their seats. They strut in all defiant, showing off, acting up, challenging the teacher's authority and physically threatening everybody. These are not isolated instances, either. It happens day after day after day after day.
The author is clearly living in a cloistered la-la land.
If I ever get transferred to a mostly black school, I'll try, God knows I'll try... but if I can't get them to cooperate, I'll quit. I've been saving money just in case.