I think the OP raises a good point. They're not murdering baby girls. They're selectively birthing boys. Different, but similar concepts. Some of this is a meme-war, where perceived hypocrisy loses points.
As long as they're only vilifying the societal pressure. I am quite hesitant to vilify a woman's choice with regards to what she chooses to carry. A woman doesn't owe 'society' a certain type of baby. A society owes a woman the ability to make the choices she wants.
It would be a mistake to assume that its usually the womens free choice.