Translation:I washed all my clothes.
so "ようふく" refers to western clothes? That seems like a strange distinction since most Japanese will be wearing T-Shirts, Jeans and what not. Is that really used? The "My" expected in the translation is also surprising to me. I assumed they're talking about all the clothe in the household or whatever.
Because the sentence is active, not passive. It might seem like no difference at all now, but it's important to realize that there is a person, not the clothes, acting as the subject here, although it is unspoken. Not making the distinction might become a problem when you get to more complicated sentences.