Very interesting question! I am not aware of any record of a woman saying/writing, "It's unfair that fashion asks us to expose parts of our bodies that men like to see." Which doesn't mean that it didn't happen, but I'm not aware of that specific complaint.

People tend to think of 18th century women's fashion as shoving the breasts up and together into a Wonderbra-esque cleavage, but to the contrary, the bust was much less prominent, usually somewhat flattened and separated. The cleavage line was in fact avoided as much as possible, and if a woman was buxom enough to have one despite the separating tendency of her stays (the 18th century foundation garment), she generally seems to have not emphasized it - though it has to be said that a certain amount of concealment went on anyway. Necklines may have been cut low in front, but in this period it was considered appropriate to wear something to cover the exposed skin. The tucker (French: tour-de-gorge) was a strip of white fabric or lace that was slightly gathered and basted into the neckline of the shift (see one on Mrs. Charles Willing, 1746; a more concealing garment was the kerchief/neck-kerchief/handkerchief (fichu), a triangle or folded square of white fabric that hung over the shoulders and met in front. (Example: Mary Miller.) Earlier in the century, the front corners were typically held under a band at the front of the neckline, sometimes descending very low and acting as a stomacher - gowns at this time opened in front, the edges generally forming a V and meeting at the waist; the stays would be covered with a triangular piece of fabric, the stomacher. By the time of the American Revolution, the front corners were often tucked in (though older or less fashionable women continued to wear the whole kerchief on the outside), and in the 1780s a very puffy kerchief that completely hid the bosom and even neck from view was in style. Another neck covering was the tippet - sometimes fur, sometimes white fabric or lace - worn like a scarf around the neck and generally crossing in front. (Princess Augusta.) While portraiture shows a lot of exposed bosom, this is a reflection of deliberate choice: most women, on most days, were not showing this skin.