Conversation so far:
what was proposed about the European Flag?
The barcode seeks to unite the flags of the EU member countries into a single, colourful symbol.
what kind of symbol?
CANNOTANSWER.
why did they decide to unite the flags?
Koolhaas and his think-tank AMO - an independent part of OMA - suggested the development of a visual language.

Question: was there any opposition to doing this?
Self-contained rewrite: was there any opposition to  the development of a visual language?