1: Because the limits are as low as they can reliably detect in man or woman. Fatigue has the same effect. I see no effort to reduce the amount of hours we can be strapped into the aircraft.
2: Drink driving limits are considerably higher and you have to try really hard to be over those limits and if you are, you are indeed drunk.
3: The new laws are not a deterrent to crews with alcohol problems. This is an illness and should be treated as such. We all have a part to play in that.
4: Finally the tabloid headlines that scream “drunk pilot arrested” are usually far from the truth…as we all know and are never put right if the allegations are subsequently found to be not true.