This isn't strictly true.
There is a good percentage of these contractors that were required to provide their services via a personal service company as a condition of their employment, the NHS being one such organisation that stipulated this. They even provided the names of service providers, to help them, which in turn were in effect UK "sales offices" for IOM / CI CSP's.
There are a significant number of ordinary people that have been or are continuing to be pursued by HMRC and have lost everything, purely because they did what they were told and in good faith.