What testimony? For example there is a fella who claims he saw mass graves at treblinka the size of 3 football fields. Satellite photos show no such disturbance, ground penetrating radar shows nothing archeological digs in the area are blocked by Israeli government. His testimony could be proven or disproven but it's not allowed. If you possessed an ounce of critical thinking skills you would have to ask yourself why? If something really did take place would it not only go to prove the story, if you are allowed to find evidence?
Most of the communists everywhere were jews.