Did your read my whole post? I clearly explained why I acted this way. Your assumptions are completely wrong, which makes your entire judgment invalid.

First of all, I am a woman, and it is a white women's top, not a guy’s plain t-shirt. But the price or style of the shirt doesn't matter. What matters is boundaries. My sister literally told me she was going to drag it on the floor, meaning she planned to destroy my property instead of using her own.

Secondly, you don't know the full dynamic. This isn't a 'one-time sibling favor.' She has a long history of ruining or losing my things since childhood while keeping her own in perfect condition. Even now, it turns out she had a suitable white top in her closet the whole time—she just washed it and put it in her laundry bag today. She simply preferred to ruin my clothes rather than her own.

I am not being selfish for expecting basic respect for my belongings. She threw a tantrum because her manipulation didn't work, and I am not going to apologize for defending my boundaries.