You're right that "the left lung" should obviously be the lung on the patient's left. However, can you look at the image below and immediately identify which is the "left" lung?
The orientation is screwed up and images should almost never be displayed like this.
If the patient’s organs are in non-standard locations (situs inversus, dextrocardia etc), something very bad will happen when orientations are messed with. Use standard orientations and label the images.
Your point was well made.
I'd also assume it would be simple to spot just because the image is always took from the same direction so the narrow part points out to front/back of the patient