Well if I was lucky enough to see what was really beneath the bra, it'd be a little weird if it turns out they weren't what I expected.
If it's what you expect, what's the point in looking in the first place?
However I also don't objectify women as much as your examples, and if someones first thought when they see an attractive women is "I'd hit that any day of the week!" then they need to grow up.
Judgemental, are we?
It has nothing to do with objectifying anyone, it is merely a statement to the effect of pointing out that, as far as one can see, with appropriate give and take on both sides, there's no prima facie reason why it should be unreasonable to believe that such physical attributes as observed by your present interlocutor be considered appealing so far as to raise the issue of generally appealing qualities being present, that one may consider sufficiently noteworthy to mention in such a context, the degree to which such an attraction would, if there was indeed any such attraction, be suitable for a metaphorical description of the same.
In short; it means I find her attractive. Now, denying it would be pointless, because I know full well what the fact of the matter is.