I don’t think it’s prudishness, I think it’s more like embarrassment and comfort. At least, comfort is my guess for the granny panties part. I don’t wear those.

I do cover up a lot as a way to hide my body. It helps to alleviate dysphoria. And I get the impression that there are a lot of other transfems here as well. Maybe there are cis girls here that cover up because they are unhappy with their appearance as well.