They set up a website and did other background stuff to establish the group.
With that sort of an offer, I'd still be looking at things like when the domain was registered, whether archive.org has any history of it, whether well-known similar organizations (CAIR, etc.) know anything about them. A $5M offer from left field just reeks of a setup.
Of course, any of you are welcome to prove me wrong with a $5M campaign contribution. I will, however, need name, address, employer and job title with that.