I don't want to stir things up, but I do think it is very important to discuss MacColl's political beliefs and how they were expressed in his music. Pete Seeger wouldn't be the beloved Pete Seeger, if he hadn't been a Communist. MacColl had a more edgy public persona than Seeger, but I have talked with a few people who knew him well and had great affection for him. The negative response to MacColl, was at least to an an extent caused by his grouchy demeanor.
I'm not really familiar with MacColl's political songs, other than those in the remarkable radio ballads. Mudcat has threads on lots of MacColl songs and many are political - and many of those political songs are quite profound.
Oh, I suppose there are a few people here who might be scandalized by MacColl's politics, but most of us have increased respect for him because of his politics.
So, certainly MacColl's politics is an appropriate topic of discussion, and should not be banished "below the line."
-Joe-