How are you defining the word “signaling?” Are you being as definitive as you sound when you say serves no other purpose, or do you mean few other purposes? Some would say that celebrities have influence they can use to champion causes they believe in.
After a certain point there is no reason to champion a cause. If a cause is popular enough people have already made up their minds and all you are doing is boosting your image among those who agree with you. You will not change a mind.
