Fear of non-conformity.

They value being in some kind of ‘tribe’ to a literally irrational extent.

Hence, black and white, ingroup vs outgroup thinking.

Then combine that with half of them hate themselves (mostly because of the peer pressure that comes from their tribe) and are literally in a suicidal apocalyptic death cult.

So when the death cult says ‘destroy’, they don’t want to lose their group identity, because without that, they are nothing, so, they destroy.