Unless you lead a perfectly “green” life I don’t think you can judge others really.
This is rubbish. It basically says that unless you do everything perfect, you shouldn't campaign for things to be just a little better.
I don't judge people who drive diesel cars any more than I judge people who drive any kind of car, even though I live on a very heavily-polluted road. (And the OP is right - pollution caused by road traffic is responsible for any number of unnecesary deaths per year.) People were told that diesel was more environmentally-sound, and it's just bad luck that the analysis of this has changed.
I do judge, a bit, people who drive any kind of car, although I do know there are valid reasons for some people having a car - including disability, etc. It's just for many people convenience has trumped everything else, and just because a trip would, eg, take an extra 20 minutes on the bus, they will hop in the car instead. It makes life a bit easier for that person, and yet makes life a little more unpleasant for us all.
And not just unpleasant, either. I really shy away from grasping the real cost of climate change, because it scares me so much. It really is something that within our lifetime could entirely change civilisation as we know it (this isn't an exaggeration) and yet in the short term, getting little Johnny to his trumpet practice on time seems to be more important.