Here's the thing though- they have said they didn't give references. That it was noted in their internal system to never employ or give references to those men again. It's entirely likely the men involved asked a mate who they used to work with for an informal reference, and those people didn't know what happened and obliged.
I recently was involved in letting someone go. We took legal advise. I would love to be able to give a honest reference on their performance as I've since learned there were similar issues in her last employment that weren't mentioned in the reference I got, but I have been advised that legally I could be sued- now there was nothing like this involved, but unless you have a high level of proof you are v limited in what you can say. In many cases, the best option is to get the staff member out as quickly as possible and accepts resignation if necessary.
Re: the high salary/small local charity division- I promise you in the majority of cases small/ local charities aren't better value, though I will say charity salaries in the international sector are lower than in the national charity one.
Let's say you have a CEO earning 120k/year, and running an organisation working in 40 countries with 5000 staff and a 100 million turnover. The 'comparable' salary of a small local charity CEO, earning maybe 40k, managing 20 staff, in reality is comparable with a much lower down staff member in the large NGO, who is also managing 20 or 30 staff and earning 40k, but has many layers above him and has to meet the same standards. There are economies of scale, more robust safeguarding measures.
As it happens, I think organisations should only be so big, and I think we need to see a reduction in the number of overseas agencies. In response to this kind of abuse, we also need much more robust systems. But it's naive to think there's a way that will stop all abuse, and by creating an incentive where once it comes out people stop donating to the charity involved- I worry about he message that will send to the next big INGO involved in a similar issue with their staff.