I disagree that there aren't enough people in IT. What I makes me annoyed is that there are many, many talented women who could be in IT or CS but who don't participate because of sexism or hostility in the workplace ecause of their gender.
It's not a matter of "lighten up". It's a matter of "stop being sexist and hostil to women". The onus is not on the victim to change her behaviour, but rather very much on the transgressors!