"Why is "glorification" a criteria for banning expression, whereas "condemning" is a criteria for "allowing" it?"

It all depends on context. Decisions are made on a team basis after discussion and taking many different points into account such as text posted with the image, title, gallery chosen, historical accuracy, and much more. 

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"you are terrifying
and strange and beautiful
something not everyone knows how to love." - Warsan Shire