Is it time to start calling out bad cyclists?

i have to have a rant because this morning whilst driving into work (which is once a year) i had 7 cyclist in front of me at a set of lights all of whom decided to race one another completely ignorant of what was behind them. They were overtaking each other oblivious of other road users! its no wonder drivers give cyclist abuse if thats what they are confronted with...

How do you know how ignorant they were?
And what exactly is the problem with 7 cyclists in front of you moving at different speeds?
Were they in your way or something?
Were you unable to pass?
Good job you only do this one day a year.