I think our society has a problem with simultaneously demonizing/sexualizing breasts based on size, from both sides of the political isle. I don't think this attitude has a positive effect on the psychological wellbeing of the female half of the population, but a formal study would be required to ascertain any measurable effects.
Not sure if serious.
Breasts are a secondary sexual characteristic in Western and some other cultures. Men like breasts. Nipples are an erogenous zone. You basically can't not sexualise breasts.
Demonising large breasts is of course a bad thing, and pretty fucked up.
It's the same thing as fat ugly chicks criticizing dudes for being attracted to "conventionally attractive" women, whatever the hell that even means. Sorry, get mad at God or something, that's just a biological reaction.
Breasts are always sexualized to some degree, but standards of beauty do differ. Some features like symmetry and clear skin are always favored, but things like preferred breast size can differ between different cultures and historical period. An ideal woman in the Renaissance would likely be considered a fat chick today. A topless supermodel with large breasts would command a lot of attention in our culture, but might not get a second glance in some indigenous cultures.
Still, regardless of whether it is biological or cultural, individual people can't fully control what they find attractive.
To BoxCrayonTales' point - there has been a lot of psychological studies on standards of beauty including breast size, but it's a politically charged topic, and I feel like a lot of the studies are even less reliable than usual for psychology. I think not demonizing is generally a good rule - and this applies just as much to unconventional standards as to conventional standards.