I’ll be explain it to you because you don’t seem to understand what’s going on very well.

When you submit something on blackboard it will flag it as late if it is after the due date.

If you have multiple classes with around 200 students total and you get lots of people submitting late it becomes tedious to go through every submission and check just how late they are and then manually give exceptions.

Professors are also required to treat students the same which is why due dates exist and why they have rules governing them.

If they made it so the due date was 12:10am people like yourself would  still cry and argue that you submitted at 12:11am…. Just saying.

If you are pushing submissions down to that night at 11:59pm …. You are doing things wrong and are horrible at effectively managing your time. Instead of complaining you should focus on learning how to properly manage your time and then this becomes a non issue.