It appears that nobody actually knows what he did after 1940 - he seems to have disappeared without trace for how many years - 5, 10, 12? We know that he was reported as AWOL but this could be deliberate misinformation put out by the authorities. Some possibilities include

• British intelligence "arranged" his desertion, and employed him on some top secret duties (did Sean Connery base his Bond on MacColl?)
• He went to Russia, and helped the Allied war effort from there
• he spent the war with the travelling community and collected much of his song collection in this time
• he was captured by a Venusian UFO and returned years later after re-programming

. In other words, we don't know. And I find it hard to condemn anyone for something if I don't he did it in the first place. If and when it is ever revealed that he was a common or garden deserter then, and only then, will I join the ranks of the condemners.