Eeeek! These things are cult over here! You can see adults spending ten minutes standing at thr table with the eggs, shaking them to their ear and try to find the one with the right surprise just for them. After they shook half a hundred eggs, they buy one, then.
Adult behave more idiotic at these opportunities than any child would ever do, so I assume the EU officials were about launching an anti-idiot-campaing, but then disliked the idea of shooing themselves in it's execution, so they focussed on the chocolate egg issue instead.