User blog comment:B214/Volume 21 info & spoilers/@comment-3965848-20160726065224/@comment-9595671-20160913060810

Well, we now know that video recordings of the battle ended up reaching the media. While the mythologies are trying to best even they have limits.

Plus I think it was stated with Azazel's memory eraser that erasing too many memories can lead to brain damage. The wizard terrorist attack in Volume 14 is such an example as many students know they were traumatized, but not the cause of it.

Trihexa's actions can't be stated as something caused by humans, so trying a mind wipe in this cause would likely risk said brain damage. Shiva pretty much implied the supernatural was undoubtedly exposed too when speaking with Ajuka.

He did mention that there are details they can't let slip out, probably things like God being dead, the deities sealed with Trihexa and such, otherwise that would tip the balance of the world and mythologies' beliefs.

Reveals like that? That definitely seems like it would risk a war, and we already got the war Indra's planning against Shiva. Imagine if Indra got more humans to side with him as a result? Especially since many would now know of Sacred Gears they could possibly have.