Is it time to start calling out bad cyclists?

on blackfriars bridge this morning heading north, massive truck with trailer indicating turning left to turn onto embankment, a few cyclists already in front of it at the red light..

I stop behind it and leave a decent gap as you can see it's indicating to go left, about ten cyclists ride past me into the cycle lane to its left, can't get to the front as you could already see and just sit there, it starts turning left/trying to but still about another ten people who can actually see it turning/what is potentially about to happen cycle straight past me presumably just expecting it to stop/thinking well it's not gonna squash all of us or maybe just oblivious..

for what it's worth i felt bad for not telling the girl on the boris bike without a helmet who was last to cycle into the gap what could happen but i lost her on new bridge street - not because i want to be sanctimonious/preachy or becuase i think i haven't made stupid mistakes before cos i have but because she may well not have known what she was exposing herself to and she's someone's kid/girlfriend/wife/mam...

I'm sometimes in this situation and have only said something once. I used to try to close the gap but that's a tad difficult when you're a titch on a titch bike, so I stopped trying. Plus the obstinate ones only force their way through as if I'm not there, giving the driver attitude along the way.