Yeah, exactly. Hmm... So..

I'm trying to imagine being the northbound driver. Say that I'm going along, see someone doing a left turn (what we would call a "left cross"), and I'm hoping to get through before the red light. I'd expect the left crosser to keep going, so I could go behind them.

But, at the last second, the left crosser suddenly stops. I don't want to try to swerve around, because there might be a third car in my blind spot to the left (this is assuming that I'm in the right hand lane) -- and/or the left crosser is blocking both lanes and I can't get around anyway since I'm not in a Formula 1 race car.

Yeah, that sucks. I'd bet that both drivers are frustrated with you now, too.

It also illustrates why some of us don't like MUPs mixing with regular intersections and riding through crosswalks. There wasn't much of another option for cyclists at this intersection, though.