@Ohhbaby Breasts are secondary 'sex organs', but a sex organ in this context doesn't mean organs we engage in our sexual activity: it is referencing sex as a noun as opposed to a verb, as in 'I'm an adult human female ‐my sex is female. As such I have XX chromosomes, produce a large gamete, and at birth, my sex is observed by a visible vulva. My primary sex organs include my ovaries and my uterus. Secondary sex characteristics include growth of breast tissue in puberty, and subsequently the capacity to lactate.'
Primary and secondary sex organs and characteristics refer to the capacity to reproduce and sustain progeny, not whether or not a body part is 'sexual' or associated with 'having sex'.
It is not 'weirdly perverted' if someone feels breasts are not sexual -that's their experience, just as TeenLifeMum believes that our nipples, if visible, are as highly sexualised as erect penises, and that the existence of wet t-shirt contests is the ultimate gotcha to anyone who disagrees, missing the point that it isn't about the men who perceive us, but about our relationships with, and the integrity of, our own bodies.
I think that context is everything, and the social and cultural constructs around female sexuality through the inescapable lens of the male gaze informs so much of our feelings about our own bodies that issues like nipples and body hair easily become problematic.