Well it does not, the verse means strike not beating. The word used is Darb which can mean to beat but it does not meaning beating. It means strike. It is also used in the phrase Darb Al-Mathal which means to set an example or set a simplitude; it could never mean beat and example!
Some Muslim men even don't understand this correctly. The Quran is saying that if a woman disobeys you continuously then you can take steps. This does not mean he can beat her. This is not part of the classical position because that was explained by the Prophet Muhammad (peace and blessings of Allah be upon him) to mean a strike that does not leave a mark.
So how can a beating without brusing? Ibn Abbas the cousin of the Prophet (peace and blessings of Allah be upon him) explained this is his commentary on the Quran as a strike that does not wound.
So if it meant beating, how can a beating not leave any mark? So it cannot mean beating can it! So it means strike but how?
One of the companions say that you should strike with a miswak which is like a twig which is used to clean the teeth.
With the Quran under your arm to make sure that you don't raise your arm because then the Quran would fall on the floor.
Men who beat their wives are some of the greatest idiots on the planet. There is a tradition that states the some men will be raised up with the tyrants even though all they had responsibility over was their families.
If people say this is why Muslim men beat their wives! Well what justification do other men use to beat their wives? Answer is this is not about religion but about men and their insecurities. Men who beat their wives need help and there is no way beating wives could ever be justified.
Any man who beats his wife had better hope that she forgives him on the day of judgement because she will have her day then.
Here's link to more details
http://www.livingislam.org/fiqhi/fiqha_e32.html
Below is a link to a lecture by Sheikh Hamza yusuf explaining Women's status in Islam.
http://sheikhynotes.blogspot.com/2007/11/sheikh-hamza-yusuf.html