Human rights protests against the 'human rights campaigner' and leader of the Labour Party Jeremy Corbyn are becoming an ever more frequent occurrence.

On Saturday, at an event in which Corbyn was set to give a speech criticising Theresa May's government for its alliance with Saudi Arabia, Corbyn faced protests over Labour's alleged fence-sitting equivocation in the face of Syrian and Russian war crimes in Aleppo.

Syria Solidarity UK, the main group involved in the protests alongside the human rights campaigner Peter Tatchell, has called on the Labour leader to "break the silence" and unequivocally condemn the bombing of Syrian civilians by the Syrian and Russian governments. The group has also called on Corbyn to support unilateral UK aid drops to besieged Syrians in Aleppo and the suspension of Syria from the UN.

As with previous hecklings of Jeremy Corbyn by left-wing anti-Assad protesters, the disruption of one of Corbyn's speeches this weekend taps into a wider discomfort with how supposedly anti-war activists respond to bloodshed which doesn't sit comfortably with their anti-American worldview. When Saudi Arabia commits human rights violations it is rightly condemned by the left. When anti-American regimes do the same, too many, including the current leader of the Labour Party, are ready to equivocate or even come down on the side of those violating human rights.

This hypocrisy, as well as the contrast between justified left-wing anger over the 2003 American-led invasion of Iraq and an almost total indifference toward to the plight of Syrians (or worse, conspiracy-mongering in which humanitarian groups like the White Helmets are smeared as part of a global Jewish/Jihadist conspiracy), betrays an ideological hangover from the farcical 'socialist' experiments of the twentieth century.

As during the Cold War, the world is divided up in the minds of left-wing activists into rival and manichean 'camps' of good versus evil. More recently, imperialist versus anti-imperialist has replaced capitalist versus socialist as the only dichotomy that matters. Thus countries like Russia, Syria and Cuba may do nasty things, but ultimately they are confronting a far greater evil embodied by the imperialistic United States and its allies.

For groups like the Stop the War Coalition, which Corbyn chaired for many years and continues to support, stopping the war has come to mean little more than ignoring it or keeping one's own hands clean. Why advertise with us

Jeremy Corbyn is very clearly influenced by this black and white method of reasoning, if you can call it that. To his starry-eyed supporters, Corbyn has consistently been on the 'right side of history' on matters of human rights, even when backing tyrants himself. Just two weeks ago the Labour leader was lavishing praise on Fidel Castro, a dictator who locked up dissenters, banned independent trade unions and took away the passports of Cubans for half a century – all grave violations of human rights.

Similarly, Corbyn has in the past praised terrorist groups like Hamas and Hezbollah and thuggish autocrats like Venezuelan leader Hugo Chavez. But as with Assad and Putin's war crimes in Syria, these are the human rights abuses it is acceptable to overlook as mere excesses in the bigger struggle between 'imperialism' and its foes.

The Labour leadership's apparent indifference to the bloody murder of hundreds of thousands of Syrians by dictator Bashar al-Assad has similarly been buttressed by a soggy 'anti-war' posture which looks hollower every day. For groups like the Stop the War Coalition, which Corbyn chaired for many years and continues to support, stopping the war has come to mean little more than ignoring it or keeping one's own hands clean.

The protest group claimed to have 'stopped the rush to war' back in 2013 when former Labour leader Ed Miliband appeared to scupper US-led military action against Assad for the sake of a short-term bounce in the polls. Since then, when the war in Syria was supposedly 'stopped', several hundred thousand people have perished under Assad's bombs. Yet even many less rigidly-minded activists seem to have accepted the idea that the mouthing of slogans is a satisfactory substitute for meaningful action, and that military inaction was inevitably without its own costs.

Well-meaning calls for a show of principle from Jeremy Corbyn over Syria are almost certainly a waste of time. It is not that the Labour leader has no principles – it is far worse than that. He is, as his supporters like so often to boastfully claim, an inflexible 'man of principle'. Yet those principles, held up as sacrosanct, are as putrescent as a maggot-ridden carcass. Corbyn and his comrades in the Stop the War Coalition inhabit a world where if the United States didn't do something then it didn't happen, or it may as well not have happened for all the attention it warrants.

'All lives matter,' declares the bigot when confronted with police violence against black Americans. 'I condemn all bombing,' retorts Jeremy Corbyn to Syrian protesters outraged by the Labour leader's silence. And just as the racist doesn't really believe that all lives matter, nor does the pacifist necessarily oppose 'all bombing'. Not if, like Jeremy Corbyn, you steadfastly oppose every initiative which might stop those who are indiscriminately dropping the most bombs.

James Bloodworth is former editor of Left Foot Forward, one of the UK's top political blogs, and the author of The Myth of Meritocracy.