Used to read his columns and admire his courage in telling the truth on foreign policy issues. Seems like the price for access to power is to be silenced and just sit back and take all the abuse that's heaped on you. Haven't seen any indication of Corbyn coming to his defense. Owen Jones apparently did, to his credit:
'a deeply insightful and thoroughly decent man who has been wronged by his media portrayal as a soulless Stalinist apparatchik'
So did Peter Wilby:
'Milne as Corbyn's spin doctor "has proved rather good at it. Most lobby journalists, initially hostile, now respect and even like him, finding his calm, courteous and expletive-free manner a refreshing change from many of his recent counterparts".' (both via wiki)
Otherwise his role seems to have been as whipping boy for the rabid right-wing press, or occasional lightning rod to take the heat off Corbyn himself. Sad. Maybe he'll write a book about it now the pressure's off? (Now it doesn't matter any more...)