Here in NJ our public school teachers are our upper middle class, and none of those I know do anything you describe. I also work by a school, and we watch the exodus at 3:01 every afternoon. No other job pays so much money for so little results; they fear competition for a reason. They are unemployable in the private sector. What you are calling “uncompensated time” is in fact the work they throw in critics’ faces, so it IS compensated; in the private sector (where we are expected to pay those teachers) we actually have unpaid overtime...
You don’t know how much work they are taking home. I know I spend several hours every weekend grading papers and entering the grades in the system on my laptop at home.