Short answer: Yes, but…
This is indeed a double standard that falls unfairly on the shoulders of women. The idea that a woman’s chest is by its very nature sexual and a male’s is not relies on framing the world solely from the perspective of the heterosexual male.
Any straight woman or gay man can tell you that a man’s chest can indeed be very sexual:
Hey girl, let’s dismantle double standards surrounding public toplessness.
This is particularly problematic concerning the issue of breastfeeding. Facebook has continuously removed images of women breastfeeding their child even when the dreaded aerola isn’t visable.
Facebook has rightly taken a lot of flack for its ban on breastfeeding photos, and hopefully the campaign to get them to change their policy (including public “nurse-ins” [1]) will be successful.
However, as other answerers have pointed out, it’s not entirely fair to blame them specifically for the ban on photos of topless women outside the context of breastfeeding, since this is based on the larger societal taboo on topless women and done solely in the interest of not angering or alienating wide swaths of potential customers. To put it another way, it is a business decision, not an idealogical one.
But this is hardly the only issue on which Facebook has been accused of misogyny. Facebook long defended it’s unwillingness to remove pages trivializing, defending and encouraging rape such as “You know she’s playing hard to get when you’re chasing her down an alleyway.”
Facebook defended its rape joke policy in a statement saying “Just as telling a rude joke won’t get you thrown out of your local pub, it won’t get you thrown off Facebook.” [2]
While Facebook eventually relented and took down some of the offending pages, all someone has to do is label their pro-rape page humor or satire, and Facebook will wholeheartly approve it. [3]
And of course, Facebook’s many misogynistic transgressions only highlight the fact that while they do have a female COO, there is not a single woman on their board of directors. [4] It’s no surprise that the concerns of Facebook’s female users are so routinely dismissed.
[1] http://www.huffingtonpost.com/2012/02/08/facebook-nurse-in-60-brea_n_1263532.html
[2] http://msmagazine.com/blog/blog/2011/11/02/notfunnyfacebook-day-of-action-against-facebooks-rape-joke-pages/
[3] http://www.bbc.co.uk/news/technology-15641998
[4] http://www.businessweek.com/news/2012-02-08/no-women-on-facebook-board-shows-white-male-influence.html