Which sin remained in them? Arrogance, pride, maybe vanity? When faced with proof (A miracle) they came up with every other explanation they could find, refusing to accept the truth right in front of them. They punished the once blind man rather than admit they were wrong.
I know people like these, those who lash out at others when faced with a truth not of their choosing rather than admit they are wrong or misunderstood. Pride is their stumbling block, their problem, but they hurt so many others in the process.