That’s a weird choice of symbol - isn’t the smiley face in Britain a sign for a drug party?
I hadn't been aware of that, but this line from the article seems to support what you say:
But parents described the decision as "PC gone mad" and demanded the "raver-style" faces be removed.
It seems that in their efforts to protect the children, they have (perhaps inadvertently) cast them in a negative light. It seems that this action on the part of people charged with teaching young people has also highlighted how out of touch they are with things....