Motorists killed around 5 people today on UK roads. And 5 people yesterday. And 5 people the day before that. And 5 people the day before that. And 5 people the day before that. And 5 people the day before that...
I can't defend that to a non motorist.
My colleague went absolutely nuts, ranting about bloody cyclists, etc. I couldn't defend them
You don't have to defend the guys with no rear lights. They're breaking the law and potentially putting themselves at risk. You can defend the majority of safe, law-abiding cyclists from your colleague's lazy stereotyping. As Michael Hutchinson said: "Why is my right to safety contingent on whether or not someone I've never met rides through a light?".