"assuming PB had a political agenda as such, unlike EM who made his political agenda his life's work and ultimately, I fear, the ruination of his craft."
To apply a little balance here, MacColl did what singers have done down the ages and sang songs which reflected his beliefs and opinions (political songs go back at least to the 10th century and are to be found in both Latin and English).
Bellamy ressurrected and sang some of the Kipling songs that helped send a generation of young men to their deaths in the trenches (until his own son was killed and he was converted to the futility of war!)
MacColl's songs largely called for a world of equality and fairness, Kipling's glorified an obscenely brutal Imperialist war - both political agendas - take your pick.
Jim Carroll