This is Lore Guide from the old forums:
be aware - massive spoilers.
There might be newer documents.
Overall you would have to go with a bit of fantasy as very little would be known to actual people and different information would be known and circulating among different people. Interpretation can differ from person to person, like someone with a particular political disposition could be thinking that source of everything is a sabotage by another government, or terrorist organization.
Those which survive would be more focused on survival than reasons for things happening.