We have only heard one side of the story - I can only bet there's more to it, especially from the Crews' point of view.
There is no way any Captain, at the start of a long night flight, is going to turn around and return to the gate, because of a silly small badge, that "nobody has noticed". There will probably have been consultations with BA security, and/or more likely the US authorities.
And I cannot believe the CSD, prior to departure, managed to examine each passengers lapels for "offensive small badges".
Interestingly this chap has a reputation... so presumably he engineered a scene, that led to.... we know the end result - not the "how".
I am curious how the usual culprits here, the TSA, let him anywhere past security, unless of course, he "chose" not to wear it through security?
NoD