I don't think companies are considered sexist based on the ratio of men/women. They're considered sexist when they _act_ sexist and don't work very hard to cultivate a good environment.
It is. Companies like Google are frequently hounded to find out 'what they are doing about their gender crisis' even though their numbers reflect graduation ratios.
I think there are a lot of groups that have an obligation to change things, but that doesn't necessarily mean they're bad either. Google is big enough to actually affect the up stream numbers, I'm glad they're working at it.