NTA although I would do as you are told, obviously. I understand your frustration though. I work at a library so we are much smaller but we've had to work on reorganizing our vacation policy because of this. It got so bad that people would just take off for 2 weeks and peace out leaving just 2-3 people to scramble to cover them. During this time it meant the 2-3 people covering them couldn't go anywhere or even so much as get sick; and god forbid if anyone else got sick. There are many places where this shit doesn't happen, and in fact prior to working here I had never seen this tolerated - you always put in for the time off and hoped it was approved. It sure af motivated you to submit your vacation request the second you knew you were booking flights/hotels/whatever, I never would have asked for time off 1-2 weeks beforehand unless it was for something like visiting a very sick family member who may pass away. But to take off on a vacation? Hell no. It was a great way to get laughed at and rejected.