Is it time to start calling out bad cyclists?

In terms of what to say to cyclists, I tend to either lie ("someone I know was badly hurt doing what you're doing") or smile and suggest that they're, for example, more visible in the middle of the lane at a junction- focus on how they could do things better rather than what they're doing wrong. Suggesting cycle training can go down quite badly, but I tend to emphasize the fact that it's free, seems to take the edge off.

Oh, and I told off a PCSO for stopping with his foot on the kerb at some lights the other day- asked incredulously- "don't you guys get cycle training?" he told me his positioning was "quicker" (???) and I sweetly suggested he should be setting an example with his riding. To which his colleague yelled "you've been TOLD, bruv!"
Weird.

There are some of them here that only cycle on the pavement...not kidding,
trying to get them trained National Standards but guess what? no dorrar...

You're not seriously advancing this as an argument are you? I will do what I do because what I do is what I do and therefore that is what I will do because what I do is what I do and so that is what I will do.
Personally I don't do the things I don't do because they are things I don't do and if I did them they would be things I do and not things I don't do and I don't do things I don't do.
Ever read CycleCraft by Donald Rumsfeld?

you are too clever by half :-)