A matter of taste really.
Songs like Ballad of Accounting, Brother Did You Weep, Fields of Viet Nam, The Island, Sharpville, Jimmy Wilson....... loads of others are political markers as to what was going on in the latter half of the 20th century - many others, as with many traditional political songs, were for the moment and quite often had no reason to continue once that moment was past.
P O'B'ws point was that songwriters had no business in interfering in with political events which should be left to the people themselves, which is utter nonsense.
Many of us where incensed with what was happening in Apartheid South Africa, Viet Nam, The Miners Strike, Chile, Greece.... and were only too glad to have good well-crafted songs which enabled us to give vent to our anger.
MacColl was persistently the finest polemicist on the scene - there has never been IMO anything as strong as well as so artistically perfect, as near as dammit, as 'White Wind' (not really a single song).
Songs like Freeborn Man, Dirty Old Town, Manchester Rambler, all making political statements, have remained standards on the folk scene decades after they were made. It's always surprised me that Tenant Farmer and Ballad of the Carpenter, two other political pieces, weren't more popular than they were.
Some of MacColl's (and Peggy's) songs were heavy-handed, but they did the job they were intended for and I can't think of one of them being a real flop.
Peggy's 'Song of Choice' remains, for me, one of the finest political songs ever written (alongside Jack Warshaw's Allende's Song).
Can't remember having heard Bellamy's 'Farewell To the Land', but I wouldn't have sought it out as I was never enamoured to either his singing or his politics.
All in the ears of the listener I suppose.
There are a number of excellent chapters in Ian Watson's Song and Democratic Culture In Britain which I would highly recommend to anybody interested in the subject.   

Jim Carroll