My (23F) boyfriend (24M) asked me to change my insta pfp

So lately my bf has been reluctant to ask me, but he finally did. He asked me to change my profile picture on instagram. To clarify, my pfp is me with my twin brother standing next to each other at an airport. I was absolutely staggered by how serious he was. He said it’s inappropriate to have any family related male in a profile picture, because it gives the wrong impression. I told him there’s obviously no way I’m changing it, then he got angrier. He said he was hurt by me dismissing his concerns and is now insisting I change it. I’m struggling to see his point, and that’s because he’s super insistent, otherwise it just sounds so insane and bizarre.

Is there a point I’m missing?

Edit. By the way, just to add — the reason why this is my pfp is because my brother and I have been living in different countries for 6 years. Being apart hurts, so this picture carries a lot of memories and emotions. We get to meet once a year if we’re lucky.