I suspect some will claim that they were victims of what might be termed 'misselling'. Although equally the investors may not have read the small print. At it's simplest the old film schemes could be described as the equivalent of getting an upfront loan (by way of a tax refund) from HMRC that would, effectively, be repaid over a 15 year period. The law was changed in 2006.
The problem is that, prior to the rule change, many advisers and investors focused only on the upfront tax refund. Investors either did not understand or chose to ignore the longer term cashflows. These were always going to result in tax being paid on profits from the film - and there had to be an expectation of profits or the scheme would not have been commercial. The profits would not be paid out however so the investors have to pay the tax out of their own resources - hence the confusion I noted earlier.