Remember when the .tk TLD became free 20 years ago ? Every hobbyist took one, then scammers followed, then Facebook and antiviruses started blocking it. I remember publishing a website for a class on my .tk domain, the teacher couldn't open it and I almost got a failing grade because of it.
A friend almost failed an IT class because his website didn't render at all in IE6. This was during the time of IE9. The teacher just hadn't updated their browser in a long time. I don't get how you get to be an IT teacher without knowing the most basic troubleshooting steps to get assignments to run.
Later versions of Internet Explorer had compatibility mode, but it often wasn’t enough to get things working, especially if there was ActiveX involved or the security policies were restrictive.
Schools were especially prone to this due to their limited budgets among other reasons, and IT teachers weren’t normally the decision makers who could do anything about it. You shouldn’t assume that a random IT teacher had the authority to spontaneously upgrade a school computer that needs to be used for things besides that one student’s assignment.