Really. People. Get over yourselves.
Sexism is a two way street. And every time someone says "girls" it's not sexist. And no, I'm not defending one way or another. This latest stink about someone saying "I've a hard time explaining to girls what we do" was almost certainly not sexist. It was a generalization. Everyone makes generalizations, even girls. As software developers, it's a pretty simple fact. Out of all the people we meet in our line of work, the majority of females are less inclined to understand what we do exactly, than the majority of males. Is that sexism? No. Would it be called sexism by girls, were it to be stated by a female? No. Is it being called such because it was stated by a male? Yes. But in the end, it was a simple generalization based on the same experience we all have to deal with. And you know what... we need quit crying wolf, and deal with it.
But we don't all need to walk on eggshells every day of our lives, in every interaction we post on a blog, or every line we speak when giving a talk. That will never solve the problem. It will only cause more and different problems. Because the world isn't androgynous. It's not how the world works. So get used to it already. If someone does say something that you personally have taken offense to, then you need to deal with it in an appropriate manner. We're all adults here (well, mostly anyway). You should contact that person privately, and discuss the matter in a rational manner. Blogging and making a fuss about every little instance of the word 'girl' on the internet isn't appropriate, nor is it going to help. If either party cannot discuss the matter rationally, then perhaps the issue needs to be escalated in an appropriate manner. Twitter, blogs, or whatever other widely published means, are probably not appropriate, because they are inherently irrational. If you truly want to help put an end to sexism, then being sexist isn't the way to go about it.
Out of all the sexist people I've met in my life, the majority were female.