To me it's the shocking attitude that without even admitting wrongdoing "well, other people are even worse".

So that means as long as we're not the worst example of any wrong behavior it's ok? I slow at a red light and hit a pedestrian "well, other riders don't even slow down" so that makes it ok.

What part of don't drink and drive don't they understand?

Two people and the lives of all their family and friends are changed forever and it's "well she's not as bad as Suzie or Joe, they don't even have a cuppa coffee first". Does that make these riders any better off that their assailent could have been a little more drunk? Are MM_QFC and her partner a little less injured because some drivers are even more distracted and irresponsible.