A lot is. Contrary to your comment, programmers have to interact with other people in order to participate in the industry, whether they're in college learning or have just taught themselves and are looking for a job. I've had quite a few female friends tell me about high school teachers and college professors who told them, straight to their faces, that programming was "for men" and they don't belong. There are still plenty of male employers who pass over perfectly qualified candidates just because they're women; plenty of male classmates who harass women with "get back in the kitchen" jokes. One of my friends even dropped out of the program all together because of it.
> Why don't we try to make this profession more interesting to everybody, instead of focusing on just 50% of the people?
Because in order to make it more interesting to everybody, we need to even out our numbers. Otherwise, when we open up the field to everyone, all we're going to do is inflate the numbers without changing the ratio.
The total number isn't the problem; it's the ratio.