Curate, connect, and discover
I believe the female version of this Katsuki will have her goods out all the time. Izuku just has to deal with it.
(In actuallity her people have freedom to choose how to present themselves and she usually wears armour or bandages since she is ready to fight at any moment. Not out of shame, out of safety. She just likes picking on Deku since her reactions are funny as hell. And maybe being vulnerable and open like this is a part of a courting process. Maybe Mina and Kirishima know this. Maybe they assume Izuku knows this as well. She really doesn't)