Is it time to start calling out bad cyclists?

I didn't need to answer, it is not a single lane road and there is a wrong side of the road. The roads do not have white lines anywhere in the forest, irrespective of width.
The road in particular is easily over two cars wide and passing cars in opposite direction doesn't even require a reduction in speed.

No use trying to defend the cyclists on this one I'm afraid. They were clearly in the wrong, made worse by their gestures and not helping other drivers attitudes to cyclists (which as said before is pretty shit to start with!)

You did need to answer. I've been on skinny lanes where riding two-abreast would take the whole "road". Oncoming cars generally pull into the passing areas to let us through in single file. Now and then they don't, of course.