Is it time to start calling out bad cyclists?

I presume you did remind the guy that if someone is on a crossing you do not go over it, even if you think it is safe... you must wait until they have finished crossing and are back on the pavement. But he did not accept the advice?

The pedestrian has the right of way when on the crossing - it does not mean that vehicles are not allowed to go through.

If a pedestrian is on a crossing, vehicles are not permitted to overtake other waiting vehicles in order to go through the crossing.