First of all, the word attraction is different from love. The case of why men are attracted to women with large breasts is totally different from why men are in love with women with large breasts. Because there are men who will say that they do not care about the breast size when they fall in love with a girl as long as she is willing to fall what’s supporting the gem.
But the case here is “attraction to large breasts”, meaning, a superficial attention to women with large breasts due to lust and social standard. Comedy shows usually use breast jokes as if the two twins are given by the Creator to be laughed about. Yes, it’s funny, but not at all times, because men usually focus their eyes on big boobs when talking to women with bigger size.
But everything has a history, dated back 35,000 years ago, paintings of nude women with large breasts and hips were discovered Paleolithic cave. These images seem to have men believed that women with larger breasts and hips are a better reproductive bet. From there, perception about big breasts evolved.
In biology, men are the only mammals fascinated about breasts, and women are the only female mammal whose breasts become enlarged upon reaching puberty. Men are fascinated about it because they know women love them to be caressed and stimulated. Nipples have thousands of nerve endings which once stimulated can create explosion, and this is why men love stimulating them. They love the reward of caressing big breasts, the reward of pleasuring women.
Another thing is, human minds are attracted to shapes and curves, and once men see big breasts their brains signal them that the women are in good health and shape. So no doubt, there are men who are attracted to women with big breasts.