Getting drunk and then causing harm to someone is different than getting drunk and being assaulted.  
Interestingly the courts have treated men far more generously than women when it comes to levels of drunkeness.  In cases outlined in the attached link, men were found to be too drunk to appreciate their actions when they assaulted women and beat the charges.  Sad.

http://www.theglobeandmail.com/news/national/judge-reinstates-controversial-drunkenness-defence-in-sex-assault-case/article578863/