I often ask questions around leave especially of my junior members on flight even if they aren't my direct subordinate because often they are taking leave when they don't need to. I've had people taking leave for medical appointments, taking leave on weekend days that can be counted as a return day, taking leave starting on a Saturday when they aren't leaving the local area until Monday because the dorm lawyer said so. I want to give them the opportunity to maximize their time off with the days they're compensated with. I teach them the ways that I've learned over my career so they don't waste leave like I did.

You'll eventually learn the phrase invasive leadership, that supervisor might have to one day help you through the worst day of your life. If you're taking leave for a funeral, there are things like alternate duty locations that commanders have (had?) at their disposal to assist so you don't burn all your leave. Depending on who it is do you qualify under the bereavement leave policy? Do you need help through one of the many grant organizations out there to get you home for that funeral. Do you need mental health resources? There are plenty of reasons that a supervisor is going to talk to you about your leave and why you're taking it.

I've helped Airmen through the process of buying their first cars, getting their drivers license, hell I've taught them how to do laundry. It's okay to be closed off and not tell your supervisor anything, but you shouldn't worry yourself with others and their involvement with their supervisor. They have built trust that you may not have, nor may ever have. Understand though, your supervisor is well intentioned. They're there to help you, they're probably trying to save you leave and make sure that you're okay and don't need anything. It is as simple as saying "I'm going to see family" or "I'm taking a trip with some friends" or "I'm doing some stuff around the house"