It's somehow related to our
Puritan culture roots.
Anything relating to sex is
BAD.
To compliment a
woman on her
breasts means you have seen them. If you have seen them enough to formulate a compliment, you must have paid some kind of
attention to them. If you paid that much
attention to them, you must have been staring at them. If you were staring at them, you must be some kind of
pervert pig. And being a
pig is bad.
That's usually how the
logic goes. Sad but true, since
female breasts are
beautiful, and I'm still not sure why women are
averse to hearing it.
I don't see how it's any different than complimenting a guy on his
muscles or his
chest, which is acceptable. Or even complimenting a girl on her
hair, which is also acceptable.