Clayton Cramer makes a good point:
Honor killings are done to earn the respect of other members of the Muslim community--to expiate shame for what their daughter (apparently, never the son) has done. By this fact alone, it tells us that honor killings are considered acceptable or even necessary by some non-trivial fraction of the Muslim community in Britain.
This matter is very tough to comprehend. We wouldn't even think of penalizing, let alone killing, a woman who after divorcing an abusive husband starts dating a man from a different village. But for many in that closed culture, the boundaries for a woman are set whether they be physical or sensual. The punishment for breaking the shackles has to be dire and swift, so as to clearly remind all the rest to stay in their place.
Cramer is also correct in noting that this horrific standard doesn't apply to the men. A sick demonstration of this:
Today I was visiting the Center for Strategic Studies at the University of Jordan and my roommate, we’ll call her Sally, went with me because she had to meet with the same professor as I.
She started crying in the taxi on the way back home telling me about her experience the other night with her Jordanian boyfriend, we’ll call him Malik.
Sally and Malik haven’t been dating for very long and I won’t go into the details of their relationship, but she really did like this guy, and I liked him as well. He seemed very Western, spoke English well, acted respectably, dressed nice, came from an affluent and well-off family. He even lived in Europe for two years and had relationships with girls there.
They went out to eat last night and she brought up the subject of honor killings. Malik nonchalantly said that he would be willing to kill his sister or support his uncle or dad if they killed her if she had sex.