I love both the poem and your feminist
rant insights, Julie!
At first I thought this was just a whimsical little poem about a pair of butterfly-print panties swirling around and around in the wash. (I don't mean "just" in a dismissive way; a poem can be a small, pleasing thing, and that's certainly better than what a lot of poems are.) Then I thought some more about that word "fading." That made me think of the
endangered monarch butterflies - but like you said, it's not pinned down (sorry!) to one interpretation.
Gender aside, the undies are tiny, which I assumed meant they were an adult's sexy undies (though you're right, they could be a child's). For me, sexy undies + the title suggests it's about the narrator's relationship history (a repetitive cycle of short-lived relationships). Or it could be about fading beauty, or lost innocence. Maybe the poem is about all these things. It works on a purely superficial level, too.
p.s. Ann, I'm still thinking about that "of color," too. Like you said, it's repeated, it seems to be significant. Maybe the point of that line is to differentiate that particular garment from the others, to show that it stands out in the crowd, while at the same time giving us a fuller picture of a load of colored wash. The relationship is fading, this lover is beginning to blend in with all the rest... I don't know, just a thought.
p.p.s. Roger, Google Translate tells me that "estampa" means stamping, stamp, print, or imprint. In English, fabric with butterflies printed all over it would be called a butterfly print or a butterfly pattern. But even if you're using, say, a rubber stamp to create one lone image at a time, there's still the implication that the individual print is not a unique creation, but one of a series of identical images, i.e. part of a pattern.