Another form of diminishing the abolitionists is to imply that they just get the credit for it because they are white* and in actual fact slavery was really undermined by slave rebellions such as in Haiti. This is was not what happened, slave revolts were damaging to the cause of anti slavery because the brutality that frequently ensued terrified the opinion formers of they day as to the consequences of letting slaves run free. Anyway slave revolts had been a recurrent problem for over 2000 years, Spartucus most famously, and slavery showed few signs of abating in that time.
It may be a result of my political predjudices but I have always associated the sneering faction with left, so I am pleasantly surprised to come across this superb article on the British Abolitionist movement in the left wing American publication Mother Jones that does justice to the almost unprecendented selflessness and altruisn that drove the campaign.
Uprisings of the oppressed have erupted throughout history, but the anti-slavery movement in England was the first sustained mass campaign anywhere on behalf of someone else's rights. Sometimes Britons even seemed to be organizing against their own self-interest. From Sheffield, famous for making scissors, scythes, knives, razors, and the like, 769 metalworkers petitioned Parliament in 1789. Because their wares were sold to ship captains for use as currency to buy slaves, the Sheffield cutlers wrote, they might be expected to favor the slave trade. But they vigorously opposed it: "Your petitioners...consider the case of the nations of Africa as their own."The essay is a couple of years old but has been put back up in time for the anniversary.
* There were several important black abolitionists, but the idea that their contribution has been unfairly overlooked in favour of less deserving white abolitionists is not the case.