Spokesperson ... for the error sex

Ruth Walker makes a great point at Verbal Energy on the word spokesperson. Why not the more specific spokesman or spokeswoman?

It illustrates the way we seem to be losing an ability to discriminate intelligently between gender-specific language and gender-exclusive language; that is, between language that adds detail and language that excludes.

To be a spokesman or a spokeswoman for an official entity, or even a flaky celebrity, is literally to stand before the press and the public, as a presence with a voice and a gender identity, and to speak with authority for someone else. One who isn't upfront enough, and out front enough, to be identifiably man or woman isn't a spokesman or spokeswoman. He or she is at best a faceless, nameless, voiceless official; or an unnamed source, maybe a snitch.

Add this to the fact that people tend to remember to write spokesman for the men but render the noun sexless for women. What gives?