Is it time to start calling out bad cyclists?

You're right. The problem with the junction is that the left hook won't happen straight after the lights, you go on for a bit after the traffic lights, then cars will follow the curve of the road to the left without indicating.

Nothing at all to do with the cyclists.

In a way you're right. The 'left turn' into Camberwell New Rd doesn't look or feel like a left turn either cycling or driving but as a continuation, whereas the continuation onto Brixton road feels and looks like a right turn.
However there are plenty of junctions in London which are confusing and potentially dangerous and that's where you have to be most alert and really pay attention to road position.
I can't recall if there are two direction arrows in the left lane but turning(or continuing) on to Brixton road from the extreme left of the left lane is daft. I've been cycling through this part of London for years (and years) and if I'm heading down to Brixton I will get into the right lane or take the left lane and if the lights are red (which is the situation I was talking about) I would use the ASL to take a visible and central road position.