There's so many possible reasons for her to think that. Including what seems appropriate, what you look like to her when you wear whatever, what style preferences she has and the list goes on. Adults can decide what they like but shouldn't be shocked if others don't find the same look appealing.
I love seeing women in thong type bottoms sometimes. But not always. Body shape, environment, age(this leans more into I don't want them to be/look too young), the fit of the suit, and the wearers comfort level all have a huge impact on whether I want to look at them.
My wife doesn't like the new trend of shorts getting shorter on men that many teens and twenties are wearing. She says it looks awkward to her because it doesn't look masculine.
Style changes and it's very wearer and viewer dependant.
