It's another one of those Damned If You Do, Damned If You Don't situations that political correctness continually foists upon us. This supervisor sent an email to his female employee suggesting that she was revealing too much cleavage, and thus is condemned as an oppressor swine. On the other hand, if he had sent a note complimenting the woman on her wardrobe choices -- "Hey, love that low-cut top! Enjoying the show! You've got a great rack!" -- this, too, would have offended feminist sensibilities.
UPDATE: Welcome, AOSHQ Morons!
Q. How does a radical feminist screw in a lightbulb?