"Perhaps because the judge agreed that Assange's conduct could not have been predicted by any reasonable person"
In court there were several arguments put as to why individual sureties would suffer great hardship if required to pay the full amount. They claimed that they acted in good faith when agreeing to the bail arrangements, and that subsequent events were totally unforeseen. Their claim was that if they had exerted pressure on Assange not to seek asylum they might have forced him into a situation where he was in danger, and that it would have been inhumane for them to have done so.
The judge said that having heard from the sureties he was in no doubt about their integrity, and that he would take some account of it. he accepted that they had all trusted Assange, and that they had followed the necessary procedures in maintaining contact with him. Nevertheless, he made the point that they has all failed in their duty to ensure that Assange surrendered himself as required. He pointed out that the courts had made it clear from the outset that they believed there were substantial grounds for believing Assange would abscond.
The various sums that were imposed took into account the personal circumstances of each surety.