Or, perhaps - the only times you ever see breasts is immediately before sex or masturbating, so you're accustomed to seeing them sexually. If I see a pec however, is more likely to be a chav drinking Carling on a hot day wearing adidas joggers.
Next, you absolute misogynistic flower, women also have sexual reactions to things - but we don't feel the need to "ACT" on it. You wait until you are in a private place and take care of that urge if you need to. You don't think we get all hot and bothered when we see a nice pec or some abs? Sure we do. We're just taught that it's not socially acceptable to slobber after other people. Perhaps if you men were taught the same you'd find it easier to control yourself.
If you are really so incapable of controlling yourself when you see a breast - because not every single one you see in your life will not be on a woman that consents to sex with you - then you need professional help. And teaching that if you see a woman's body (or any body), your reaction isn't too pop a boner or "act" on your urges - you need to remind yourself that that wet hole you fancy diving into is, in fact, a body part of another sentient human being. You have no claim to it. If you pop a boner you don't have right to stick your penis into whatever you fancy. You're not an animal, you're perfectly capable of controlling yourself. So don't blame another person's body for your own, disgusting, lack of self control.
Tl;dr
Yes, we should be able to topless if men do ^^ free ALL the nipples, or keep all the nipples locked away. The thought that women's bodies are more sexual than men's is ridiculous. No, we are taught from a young age that men are allowed to be overtly sexual and women aren't. Change the teaching - change the thought.