Serena is a much bigger celebrity than any of those men. I've never seen Nadal's ugly mug on the cover of Vogue. Federer's profile probably would have come close 9 or 10 years ago but not lately. Serena is at the forefront of celebrity news and whatever she does is publicized accordingly, which added a lot of attention to an incident that would have been in the news anyway, regardless of who was involved.
In terms of male vs. female outbursts, I would love for somebody to do an accurate comparison of comparable incidents and demonstrate a double standard. But give me a break with the idea that the likes of Marcos Baghdatis and Victor Troiki breaking rackets in the early rounds of whatever tournament is just as newsworthy as all of Flushing Meadows booing the final of the US Open, and that we're only paying attention to the latter because of sexism.