If millions of people died and you were right there when it happened, a likely suspect, you might want to deflect blame as well.
Populism and Politics have little to do with the truth. If the masses are fired up over one theory, or if the highly politicized academic community is fired up over one of their own sensitivities, it can be destructive for many involved.
Refusing legitimate investigation - now that's a bad sign because people should want to clear their names.
We don't know what the answers are but it warrants further investigation.