Is it time to start calling out bad cyclists?

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.

In all my days of cycling i havent seen that many people overtake / pull out without looking first... ignorant, foolish, whatever...

1. no problem with 7 or 20 cyclists in front of me moving at different speeds given i do that every day myself
   
2. i was trying overtake as i was travelling faster than they were but couldn't as they were blocking the road making it unsafe for me to pass
   
3. i was unable to pass
   
4. indeed it is given i have been cycling in London for 20 years!