It’s the question I ask myself all the time.
Of course being aroused by breasts is natural and by no means bad in itself, let’s make it clear. But our culture skewed the perception of breasts by overemphasizing their arbitrary* sexual value (*boobs are not necessary for sex to happen, after all). They’re treated like some kind of secondary genitals, while tabooing the actual function they’re designed for (feeding babies).
That’s the sad reason why on one hand a bare female breast is considered “indecent” to the point of shaming women from nursing in public places, while on the other hand they’re used as a shortcut for what straight male audience would (allegedly) instantly find appealing.
And as (horny) hetero men are somehow the default audience for most of entertainment media, boobs need to be bared, or at least emphasized beyond any logic (and beyond how science works) on every possible occasion, even when it makes little to no sense in context.
Frustration with above school of thought is one of the major reasons that this blog exists. You know there’s something wrong when it’s more important to show that a warrior character happens to have boobs than to apply some practical battle wear for them.