This is not an act in accordance to the Sunnah and it is an innovation.
Never did our Prophet salla Allahu alaihi wa sallam encourage people to do such a congregational Du’ah.
It is recommended for every individual to call Allah and make Du’ah so that the aggression is uplifted but not to do this at that designated time as it is only time of acceptance of Du’ah only for the people standing in Arafah and not for others who are not performing Hajj.
If you want to supplicate, you can do this between the Athan and Iqamah, in the last third of the night, while prostrating or before concluding and offering Salam in prayer.
Therefore, I urge you not to help in spreading such an e-mail that would probably mislead people into such an innovation.
Besides, people would laugh at us few weeks later when they would say: look at the millions of Muslims who made Du’ah and nothing changed. We know that nothing changed because of our wrong actions and lack of sincerity.
But never give up! Allah will answer our calls and He will grant the oppressed victory.