I think it's more of a social programming phenomena. We see that breast are nuturing to an infant, making them healthy and strong. There is a vitality that exudes from the breast. Over generations, this becomes more engrained in the mentality of the womans bussom. Thus a strong connection becomes establisehd. Then food/feeding becomes somewhat synonymous with the breast. Since such a correlation exists, so does the fetish or want of breast adoration or worship. Breast, are divinely woman. Albeit there are man boobs, breasts are a sign of of comfort and appeasment. Men create much stronger visual cues and thus physical cues when exposed to a womans breast or even to food. Even in nature, animals know to feed from the breast. Areola's darken, nipples engorge etc. All this so that the child can find suckling easier. Men (the gender) have basic needs. Food, shelter, physical stimulation are the 3 primal ones. Breast cover 2 of these 3. Even sex idols of ancient society depict fertile women as being big hipped and largeley endowed in the breast. The womb, could itself depict shelter, thus satisfying the 3rd primal need of men. However, breast are much more visible to men than other parts, butt excluded. Plus they are really fun to play with. They jiggle and bouce. It's lilke a jello slinky!
you seriously thought I was going to keep this as a totally serious reply? tsk tsk.