The problem with this is that they didn't know they were losing money.
The trading had gone haywire and they didn't understand why it was doing what it was doing but at the time it was happening they couldn't say if they were making or losing money.
They built up positions of billions of dollars and only once it was all unwound and settled were the losses finally known.
I can feel for the programmers and sysadmins. Maybe this was right - maybe pulling the plug out would prevent the unwinding of positions that would then make money for the firm.
I wouldn't be surprised if there weren't previous problems where programmers and admins had been criticized by management for "doing the wrong thing with hindsight" when they didn't understand what was going on. If you have that sort of management culture then the natural inclination becomes to do nothing and push the responsibility up the chain.
Similar disasters have happened in the past - one that springs to mind was Piper Alpha where the other nearby rigs continued to pump gas to it even when they could see it was on fire - because if you stop pumping it takes days and costs a fortune to get things back up and running and it might just have been an easily controllable fire.
There's a very fine line to be drawn between reacting to the unknown too soon and reacting too late. There's also a fine line between making a reasonable best guess with the facts available and just making a random guess.
http://en.wikipedia.org/wiki/Piper_Alpha
The fire would have burnt out were it not being fed with oil from both Tartan and the Claymore platforms, the resulting back pressure forcing fresh fuel out of ruptured pipework on Piper, directly into the heart of the fire. The Claymore platform continued pumping until the second explosion because the manager had no permission from the Occidental control centre to shut down. Also, the connecting pipeline to Tartan continued to pump, as its manager had been directed by his superior. The reason for this procedure was the huge cost of such a shut down. It would have taken several days to restart production after a stop, with substantial financial consequences.