I have seen deadlines wrap all the way around a 24 hour cycle in this way. 5 PM is bad because people want to work at night, so delay to midnight. Well, people aren’t finishing, so delay to 5 AM, since everybody would be asleep then. Well now people are blaming you for “forcing” them to do all nighters, so delay to 9 AM. Now people say that’s unreasonable, because submitting later in the workday wouldn’t hurt anyone. So delay to 5 PM.
In my undergraduate education, toxic behavior like this was common. One professor who was a particular asshole deliberately assigned onerous assignments to coincide with an assignment for another critical, difficult class that 75% of the students were taking. Academic hazing was pretty common in CS.